Schizophrenia ( or ), from the
GreekAncient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...
roots
skhizein (
σχίζειν, "to split") and
phrēn, phren- (
φρήν, φρεν-; "mind") is a
psychiatricPsychiatry is a medical specialty officially devoted to the treatment and study of mental disorders. The term was first coined by the German physician Johann Christian Reil in 1808....
diagnosis that describes a mental disorder characterized by abnormalities in the perception or expression of reality. Distortions in perception may affect all five
senseSenses are the physiological methods of perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...
s, including sight, hearing, taste, smell and touch, but most commonly manifest as auditory
hallucinationA hallucination, in the broadest sense, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and...
s,
paranoidParanoia is a thought process heavily influenced by excessive anxiety or fear, often to the point of irrationality and delusion. Paranoid thinking typically includes persecutory beliefs concerning a perceived threat towards oneself. In the original Greek, παράνοια simply means madness...
or bizarre
delusionA delusion, in everyday language, is a fixed belief that is either false, fanciful, or derived from deception. Psychiatry defines the term more specifically as a belief that is pathological...
s, or
disorganized speech and thinkingIn psychiatry, thought disorder or formal thought disorder is a term used to describe a pattern of disordered language use that is presumed to reflect disordered thinking...
with significant social or occupational dysfunction. Onset of symptoms typically occurs in young adulthood, with approximately 0.4–0.6% of the population affected. Diagnosis is based on the patient's self-reported experiences and observed behavior. No laboratory test for schizophrenia currently exists.
Studies suggest that
geneticsGenetics, , a discipline of biology, is the science of heredity and variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding...
, early environment, neurobiology,
psychologicalPsychology is an academic and applied discipline involving the systematic, and sometimes scientific, study of human or animal mental functions and behavior...
and social processes are important contributory factors; some recreational and prescription drugs appear to cause or worsen symptoms. Current psychiatric research is focused on the role of neurobiology, but no single organic cause has been found. As a result of the many possible combinations of symptoms, there is debate about whether the diagnosis represents a single disorder or a number of discrete syndromes. For this reason,
Eugen BleulerPaul Eugen Bleuler was a Swiss psychiatrist most notable for his contributions to the understanding of mental illness and coining the term schizophrenia....
termed the disease
the schizophrenias (plural) when he coined the name. Despite its etymology, schizophrenia is not the same as
dissociative identity disorderDissociative identity disorder is a psychiatric diagnosis that describes a condition in which a single person displays multiple distinct identities or personalities , each with its own pattern of perceiving and interacting with the environment...
, previously known as multiple personality disorder or split personality, with which it has been erroneously confused.
Increased
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
activity in the
mesolimbic pathwayThe mesolimbic pathway is one of the dopaminergic pathways in the brain. The pathway begins in the ventral tegmental area of the midbrain and connects to the limbic system via the nucleus accumbens, the amygdala, and the hippocampus as well as to the medial prefrontal cortex...
of the brain is consistently found in schizophrenic individuals. The mainstay of treatment is
antipsychoticAntipsychotics are a group of psychoactive drugs commonly but not exclusively used to treat psychosis, which is typified by schizophrenia, but can also be present in severe bipolar disorder, as well as many other conditions. Over time a wide range of antipsychotics have been developed...
medication; this type of drug primarily works by suppressing dopamine activity. Dosages of antipsychotics are generally lower than in the early decades of their use.
PsychotherapyPsychotherapy or personal counseling with a psychotherapist, is an intentional interpersonal relationship used by trained psychotherapists to aid a client or patient in problems of living.It aims to increase the individual's sense of their own well-being...
, and vocational and social rehabilitation are also important. In more serious cases—where there is risk to self and others—involuntary hospitalization may be necessary, although hospital stays are less frequent and for shorter periods than they were in previous times.
The disorder is thought to mainly affect
cognitionCognition is the scientific term for "the process of thought". Usage of the term varies in different disciplines; for example in psychology and cognitive science, it usually refers to an information processing view of an individual's psychological functions...
, but it also usually contributes to chronic problems with behavior and emotion. People with schizophrenia are likely to have additional (
comorbidIn medicine, comorbidity is either:* The presence of one or more disorders in addition to a primary disease or disorder; or* The effect of such additional disorders or diseases....
) conditions, including major depression and
anxiety disorderAnxiety disorder is a blanket term covering several different forms of abnormal and pathological fears and anxieties which only came under the aegis of psychiatry at the very end of the 19th century. Current psychiatric diagnostic criteria recognize a wide variety of anxiety disorders...
s; the lifetime occurrence of
substance abuseAlthough the term substance can refer to any physical matter, substance abuse has come to refer to the overindulgence in and dependence of a drug or other chemical leading to effects that are detrimental to the individual's physical and mental health, or the welfare of others.]The disorder is...
is around 40%. Social problems, such as long-term unemployment, poverty and homelessness, are common. Furthermore, the average
life expectancyLife expectancy is the expected number of years of life remaining at a given age. It is denoted by e
x, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...
of people with the disorder is 10 to 12 years less than those without, due to increased physical health problems and a higher
suicideSuicide is the intentional killing of one's self. Many dictionaries also note the metaphorical sense of "willful destruction of one's self-interest"...
rate.
Signs and symptoms
A person diagnosed with schizophrenia may demonstrate auditory
hallucinationA hallucination, in the broadest sense, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and...
s,
delusionA delusion, in everyday language, is a fixed belief that is either false, fanciful, or derived from deception. Psychiatry defines the term more specifically as a belief that is pathological...
s, and
disorganized and unusual thinkingIn psychiatry, thought disorder or formal thought disorder is a term used to describe a pattern of disordered language use that is presumed to reflect disordered thinking...
and speech; this may range from loss of train of thought and subject flow, with sentences only loosely connected in meaning, to incoherence, known as word salad, in severe cases. Social isolation commonly occurs for a variety of reasons. Impairment in
social cognitionSocial cognition is the study of how people process social information, especially its encoding, storage, retrieval, and application to social situations. Social cognition’s focus on information processing has many affinities with its sister discipline, cognitive psychology...
is associated with schizophrenia, as are symptoms of paranoia from delusions and hallucinations, and the negative symptoms of
avolitionAvolition is a psychological state characterized by general lack of desire, drive, or motivation to pursue meaningful goals. It is commonly seen in patients with schizophrenia, and is one of the four main "negative" symptoms of that disorder. Other characteristics are flat affect, alogia, and...
(apathy or lack of motivation). In one uncommon subtype, the person may be largely mute, remain motionless in bizarre postures, or exhibit purposeless agitation; these are signs of
catatoniaCatatonia is a syndrome of psychological and motorological disturbances. Karl Ludwig Kahlbaum first described it in 1874: Die Katatonie oder das Spannungirresein...
. No one sign is diagnostic of schizophrenia, and all can occur in other medical and psychiatric conditions. The current classification of psychoses holds that symptoms need to have been present for at least one month in a period of at least six months of disturbed functioning. A schizophrenia-like psychosis of shorter duration is termed a
schizophreniform disorderSchizophreniform disorder is a mental disorder diagnosed when symptoms of schizophrenia are present for at least one month but not for the full six months required for the diagnosis of schizophrenia. The symptoms of both disorders can include delusions, hallucinations, disorganized speech,...
.
Late adolescence and early adulthood are peak years for the onset of schizophrenia. In 40% of men and 23% of women diagnosed with schizophrenia, the condition arose before the age of 19. These are critical periods in a young adult's social and vocational development, and they can be severely disrupted. To minimize the effect of schizophrenia, much work has recently been done to identify and treat the
prodromal (pre-onset)In medicine, a prodrome is an early non-specific symptom that might indicate the start of a disease before specific symptoms occur. For example fever, malaise, headache and lack of appetite frequently occur in the prodrome of many infective disorders...
phase of the illness, which has been detected up to 30 months before the onset of symptoms, but may be present longer. Those who go on to develop schizophrenia may experience the non-specific symptoms of social withdrawal, irritability and
dysphoriaDysphoria is an unpleasant or uncomfortable mood, such as sadness , anxiety, irritability, or restlessness. Etymologically, it is the opposite of euphoria....
in the prodromal period, and transient or self-limiting psychotic symptoms in the prodromal phase before psychosis becomes apparent.
Schneiderian classification
The psychiatrist
Kurt SchneiderKurt Schneider was a German psychiatrist known largely for his writing on the diagnosis and understanding of schizophrenia.-Biography:...
(1887–1967) listed the forms of psychotic symptoms that he thought distinguished schizophrenia from other psychotic disorders. These are called
first-rank symptoms or Schneider's first-rank symptoms, and they include delusions of being controlled by an external force; the belief that thoughts are being inserted into or withdrawn from one's conscious mind; the belief that one's thoughts are being broadcast to other people; and hearing hallucinatory voices that comment on one's thoughts or actions or that have a conversation with other hallucinated voices. Although they have significantly contributed to the current diagnostic criteria, the
specificitySensitivity and specificity are statistical measures of the performance of a binary classification test. Sensitivity measures the proportion of actual positives which are correctly identified as such...
of first-rank symptoms has been questioned. A review of the diagnostic studies conducted between 1970 and 2005 found that these studies allow neither a reconfirmation nor a rejection of Schneider's claims, and suggested that first-rank symptoms be de-emphasized in future revisions of diagnostic systems.
Positive and negative symptoms
Schizophrenia is often described in terms of
positive and
negative (or deficit) symptoms. The term
positive symptoms refers to symptoms that most individuals do not normally experience. They include
delusionA delusion, in everyday language, is a fixed belief that is either false, fanciful, or derived from deception. Psychiatry defines the term more specifically as a belief that is pathological...
s,
auditory hallucinationsA hallucination, in the broadest sense, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and...
, and
thought disorderIn psychiatry, thought disorder or formal thought disorder is a term used to describe a pattern of disordered language use that is presumed to reflect disordered thinking...
, and are typically regarded as manifestations of
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
.
Negative symptoms are so-named because they are considered to be the loss or absence of normal traits or abilities, and include features such as flat or
blunted affectBlunted affect is the scientific term describing a lack of emotional reactivity on the part of an individual.Victims of post-traumatic stress syndrome are often said to display blunted affect. Veterans of intense combat have been described as having the thousand-yard stare...
and emotion, poverty of speech (
alogiaIn psychology, alogia , or poverty of speech, is a general lack of additional, unprompted content seen in normal speech. As a symptom, it is commonly seen in patients suffering from schizophrenia, and is considered as a negative symptom...
), inability to experience pleasure (
anhedoniaIn psychology, anhedonia is an inability to experience pleasure from normally pleasurable life events such as eating, exercise, and social or sexual interaction....
), lack of desire to form relationships (
asocialityAsociality is a negative symptom frequently observed in schizophrenia patients. It is characterised by an inability to 'empathise', to feel intimacy with, or to form close relationships with others ....
), and lack of motivation (
avolitionAvolition is a psychological state characterized by general lack of desire, drive, or motivation to pursue meaningful goals. It is commonly seen in patients with schizophrenia, and is one of the four main "negative" symptoms of that disorder. Other characteristics are flat affect, alogia, and...
). Research suggests that negative symptoms contribute more to poor quality of life, functional disability, and the burden on others than do positive symptoms.
Despite the appearance of blunted affect, recent studies indicate that there is often a normal or even heightened level of emotionality in schizophrenia, especially in response to stressful or negative events. A third symptom grouping, the
disorganization syndrome, is commonly described, and includes chaotic speech, thought, and behavior. There is evidence for a number of other symptom classifications.
Diagnosis
Schizophrenia is diagnosed on the basis of symptom profiles.
NeuralThe nervous system is a network of specialized cells that communicate information about an organism's surroundings and itself. It processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glial cells that aid in the...
correlates do not provide sufficiently useful criteria. Diagnosis is based on the self-reported experiences of the person, and abnormalities in behavior reported by family members, friends or co-workers, followed by a clinical assessment by a
psychiatristA psychiatrist is a physician who specializes in psychiatry and is certified in treating mental disorders. All psychiatrists are trained in diagnostic evaluation and in psychotherapy...
, social worker, clinical psychologist or other
mental health professionalA mental health professional is a person who offers services for the purpose of improving an individual's mental health or to treat mental illness. This broad category includes psychiatrists, clinical psychologists, clinical social workers, psychiatric nurses, mental health counselors as well as...
. Psychiatric assessment includes a
psychiatric historyA psychiatric history is the result of a medical process where a clinician working in the field of mental health systematically records the content of an interview with a patient...
and some form of
mental status examinationThe mental status examination abbreviated MSE, is an important part of the clinical assessment process in psychiatric practice...
.
Standardized criteria
The most widely used standardized criteria for diagnosing schizophrenia come from the
American Psychiatric AssociationThe American Psychiatric Association is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the most influential worldwide. Its some 38,000 members are mainly American but some are international...
's
Diagnostic and Statistical Manual of Mental DisordersThe Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides diagnostic criteria for mental disorders...
, version DSM-IV-TR, and the
World Health OrganizationThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health...
's
International Statistical Classification of Diseases and Related Health ProblemsThe International Statistical Classification of Diseases and Related Health Problems provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings,...
, the ICD-10. The latter criteria are typically used in European countries, while the DSM criteria are used in the United States and the rest of the world, as well as prevailing in research studies. The ICD-10 criteria put more emphasis on Schneiderian first-rank symptoms, although, in practice, agreement between the two systems is high.
According to the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), to be diagnosed with schizophrenia, three diagnostic criteria must be met:
- Characteristic symptoms: Two or more of the following, each present for much of the time during a one-month period (or less, if symptoms remitted with treatment).
- Delusion
A delusion, in everyday language, is a fixed belief that is either false, fanciful, or derived from deception. Psychiatry defines the term more specifically as a belief that is pathological...
s
- Hallucination
A hallucination, in the broadest sense, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and...
s
- Disorganized speech, which is a manifestation of formal thought disorder
In psychiatry, thought disorder or formal thought disorder is a term used to describe a pattern of disordered language use that is presumed to reflect disordered thinking...
- Grossly disorganized behavior (e.g. dressing inappropriately, crying frequently) or catatonic
Catatonia is a syndrome of psychological and motorological disturbances. Karl Ludwig Kahlbaum first described it in 1874: Die Katatonie oder das Spannungirresein...
behavior
- Negative symptoms—affective flattening (lack or decline in emotional response), alogia
In psychology, alogia , or poverty of speech, is a general lack of additional, unprompted content seen in normal speech. As a symptom, it is commonly seen in patients suffering from schizophrenia, and is considered as a negative symptom...
(lack or decline in speech), or avolitionAvolition is a psychological state characterized by general lack of desire, drive, or motivation to pursue meaningful goals. It is commonly seen in patients with schizophrenia, and is one of the four main "negative" symptoms of that disorder. Other characteristics are flat affect, alogia, and...
(lack or decline in motivation)
- If the delusions are judged to be bizarre, or hallucinations consist of hearing one voice participating in a running commentary of the patient's actions or of hearing two or more voices conversing with each other, only that symptom is required above. The speech disorganization criterion is only met if it is severe enough to substantially impair communication.
- Social/occupational dysfunction: For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning such as work, interpersonal relations, or self-care, are markedly below the level achieved prior to the onset.
- Duration: Continuous signs of the disturbance persist for at least six months. This six-month period must include at least one month of symptoms (or less, if symptoms remitted with treatment).
Schizophrenia cannot be diagnosed if symptoms of
mood disorderA mood disorder is the term given for a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
or
pervasive developmental disorderThe diagnostic category pervasive developmental disorders , as opposed to specific developmental disorders , refers to a group of five disorders characterized by delays in the development of multiple basic functions including socialization and communication...
are present, or the symptoms are the direct result of a general medical condition or a substance, such as abuse of a drug or medication.
Confusion with other conditions
Psychotic symptoms may be present with several other psychiatric illnesses, including
bipolar disorderBipolar disorder, also known as manic depressive disorder, manic depression or bipolar affective disorder, is a serious mental disorder that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated mood clinically referred to as mania or, if...
,
borderline personality disorderBorderline personality disorder is a psychiatric diagnosis in the Diagnostic and Statistical Manual of Mental Disorders that describes a prolonged disturbance of personality function characterized by depth and variability of moods...
,
schizoaffective disorderSchizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of mood disorder and psychosis. Distortions in perception alternate with and occur simultaneously with elevated or depressed mood...
, drug intoxication, either intoxicated or abstinent drug-induced psychosis, and
schizophreniform disorderSchizophreniform disorder is a mental disorder diagnosed when symptoms of schizophrenia are present for at least one month but not for the full six months required for the diagnosis of schizophrenia. The symptoms of both disorders can include delusions, hallucinations, disorganized speech,...
. Schizophrenia is complicated with
obsessive-compulsive disorderObsessive–compulsive disorder is a mental disorder characterized by intrusive thoughts that produce anxiety, by repetitive behaviors aimed at reducing anxiety, or by combinations of such thoughts and behaviors...
(OCD) considerably more often than could be explained by pure chance, although it can be difficult to distinguish compulsions that represent OCD from the delusions characteristic of the schizophrenia.
A more general medical and neurological examination may be needed to rule out medical illnesses which may rarely produce psychotic schizophrenia-like symptoms, such as metabolic disturbance,
systemic infectionSystemic infection is a generic term for infection caused by microorganisms in animals or plants, where the causal agent has spread actively or passively in the host's anatomy and is disseminated throughout several organs in different systems of the host...
,
syphilisSyphilis is a sexually transmitted disease caused by the spirochetal bacterium Treponema pallidum subspecies pallidum. The route of transmission of syphilis is almost always through sexual contact, although there are examples of congenital syphilis via transmission from mother to child in utero.The...
,
HIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid,...
infection,
epilepsyEpilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures...
, and brain lesions. It may be necessary to rule out a
deliriumDelirium is an acute and debilitating decline in attention-focus, perception, and cognition that produces an altered form of semi-consciousness. It is a systemic syndrome caused by a chemical or disease-process which is disrupting the neurons of the cerebral cortex...
, which can be distinguished by visual hallucinations, acute onset and fluctuating
level of consciousnessLevel of consciousness is a measurement of a person's arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousness may be classed as lethargy; someone in this state can be aroused with little difficulty. People who are obtunded have a more depressed...
, and indicates an underlying medical illness. Investigations are not generally repeated for relapse unless there is a specific
medical indication or possible adverse effects from antipsychotic medication.
"Schizophrenia" does
not mean dual personality, despite the
etymologyEtymology is the study of the history of words and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages, and texts about the languages, to gather knowledge about how words were used at earlier stages, and...
of the word (Greek σχίζω = "I split").
Subtypes
The
DSM-IV-TRThe Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides diagnostic criteria for mental disorders...
contains five sub-classifications of schizophrenia.
- Paranoid type: Where delusions and hallucinations are present but thought disorder, disorganized behavior, and affective flattening are absent. (DSM code 295.3/ICD code F20.0)
- Disorganized type
Disorganized schizophrenia is a subtype of schizophrenia as defined in the Diagnostic and Statistical Manual of Mental Disorders, DSM-IV code 295.10. This type is characterized by prominent disorganized behavior and speech including schizophasia, and flat or inappropriate emotion and affect...
: Named hebephrenic schizophrenia in the ICD. Where thought disorder and flat affectBlunted affect is the scientific term describing a lack of emotional reactivity on the part of an individual.Victims of post-traumatic stress syndrome are often said to display blunted affect. Veterans of intense combat have been described as having the thousand-yard stare...
are present together. (DSM code 295.1/ICD code F20.1)
- Catatonic type
Catatonia is a syndrome of psychological and motorological disturbances. Karl Ludwig Kahlbaum first described it in 1874: Die Katatonie oder das Spannungirresein...
: The subject may be almost immobile or exhibit agitated, purposeless movement. Symptoms can include catatonic stupor and waxy flexibilityWaxy flexibility is a psychomotor symptom of catatonic schizophrenia which leads to a decreased response to stimuli and a tendency to remain in an immobile posture. For instance, if one were to move the arm of someone with waxy flexibility, they would keep their arm where one moved it until it was...
. (DSM code 295.2/ICD code F20.2)
- Undifferentiated type: Psychotic symptoms are present but the criteria for paranoid, disorganized, or catatonic types have not been met. (DSM code 295.9/ICD code F20.3)
- Residual type: Where positive symptoms are present at a low intensity only. (DSM code 295.6/ICD code F20.5)
The
ICD-10The International Statistical Classification of Diseases and Related Health Problems provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings,...
defines two additional subtypes.
- Post-schizophrenic depression: A depressive episode arising in the aftermath of a schizophrenic illness where some low-level schizophrenic symptoms may still be present. (ICD code F20.4)
- Simple schizophrenia: Insidious and progressive development of prominent negative symptoms with no history of psychotic episodes. (ICD code F20.6)
Controversies and research directions
Part of a larger
controversy over biopsychiatryThe biopsychiatry controversy is a dispute over which viewpoint should predominate and form the scientific basis of psychiatric theory and practice. The debate is a criticism of the strict biological view of psychiatric thinking. Its critics including disparate groups such as the antipsychiatry...
, the validity of schizophrenia as a diagnostic entity has been criticised by number of psychologists as lacking in scientific validity and
diagnostic reliabilityIn medicine and psychology, diagnostic reliability refers to the ability of a diagnostic tool, typically symptoms, to predict an illness or disorder. It is a direct application of the notion of statistical reliability...
. In 2006, a group of patients and mental health professionals from the UK, under the banner of Campaign for Abolition of the Schizophrenia Label, argued for a rejection of the diagnosis of schizophrenia based on its heterogeneity and associated stigma, and called for the adoption of a bio-psychosocial model. Other UK psychiatrists opposed the move arguing that the term schizophrenia is a useful, even if provisional concept.
The discrete category of schizophrenia used in the DSM has also been criticized. As with other psychiatric disorders, some psychiatrists have suggested that the diagnosis would be better addressed as individual dimensions along which everyone varies, such that there is a
spectrumSpectrum disorder in psychiatry is a term used to describe a mental disorder when there is thought to be "not a unitary disorder but rather a syndrome composed of subgroups" that can range from relatively "severe" to relatively "mild and nonclinical deficits"....
or continuum rather than a cut-off between normal and ill. This approach appears consistent with research on
schizotypySchizotypy is a psychological concept which describes a continuum of personality characteristics and experiences related to psychosis and in particular, schizophrenia....
, and with a relatively high prevalence of psychotic experiences, mostly non-distressing delusional beliefs, among the general public. In concordance with this observation, psychologist Edgar Jones, and psychiatrists
Tony DavidAnthony David is Professor of Cognitive neuropsychiatry at the Institute of Psychiatry, part of King's College London.Professor David studied medicine at the University of Glasgow, subsequently training in neurology, then psychiatry...
and Nassir Ghaemi, surveying the existing literature on delusions, pointed out that the consistency and completeness of the definition of delusion have been found wanting by many; delusions are neither necessarily fixed, nor false, nor involve the presence of incontrovertible evidence.
Nancy Andreasen, a leading figure in schizophrenia research, has criticized the current DSM-IV and ICD-10 criteria for sacrificing validity for the sake of improving diagnostic reliability. She argues that overemphasis on psychosis in the diagnostic criteria, while improving diagnostic reliability, ignores more fundamental cognitive impairments that are harder to assess due to large variations in presentation. This view is supported by other psychiatrists. In the same vein, Ming Tsuang and colleagues argue that psychotic symptoms may be a common end-state in a variety of disorders, including schizophrenia, rather than a reflection of the specific etiology of schizophrenia, and warn that there is little basis for regarding DSM’s operational definition as the "true" construct of schizophrenia. Neuropsychologist Michael Foster Green went further in suggesting the presence of specific neurocognitive deficits may be used to construct phenotypes that are alternatives to those that are purely symptom-based. These deficits take the form of a reduction or impairment in basic psychological functions such as
memoryIn psychology, memory is an organism's mental ability to store, retain, and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing the memory....
,
attentionAttention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. Attention has also been referred to as the allocation of processing resources...
, executive function and
problem solvingProblem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...
.
The exclusion of affective components from the criteria for schizophrenia, despite their ubiquity in clinical settings, has also caused contention. This exclusion in the DSM has resulted in a "rather convoluted" separate disorder—
schizoaffective disorderSchizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of mood disorder and psychosis. Distortions in perception alternate with and occur simultaneously with elevated or depressed mood...
. Citing poor interrater reliability, some psychiatrists have totally contested the concept of schizoaffective disorder as a separate entity. The categorical distinction between mood disorders and schizophrenia, known as the Kraepelinian dichotomy, has also been challenged by data from genetic epidemiology.
Causes
While the reliability of the diagnosis introduces difficulties in measuring the relative effect of genes and environment (for example, symptoms overlap to some extent with severe
bipolar disorderBipolar disorder, also known as manic depressive disorder, manic depression or bipolar affective disorder, is a serious mental disorder that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated mood clinically referred to as mania or, if...
or
major depressionMajor depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and loss of interest or pleasure in normally enjoyable activities...
), evidence suggests that genetic and
environmental factorIn epidemiology, environmental factors are those determinants of disease that are not transmitted genetically. Apart from the true monogenic genetic disorders, environmental factors may determine the development of disease in those genetically predisposed to a particular condition...
s can act in combination to result in schizophrenia. Evidence suggests that the diagnosis of schizophrenia has a significant heritable component but that onset is significantly influenced by environmental factors or stressors. The idea of an inherent vulnerability (or
diathesis) in some people, which can be unmasked by biological, psychological or environmental stressors, is known as the
stress-diathesis model. The idea that biological, psychological and social factors are all important is known as the "biopsychosocial" model.
Genetic
Estimates of the
heritabilityIn genetics, Heritability is the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals. Variation among individuals may be due to genetic and/or environmental factors...
of schizophrenia tend to vary owing to the difficulty of separating the effects of genetics and the environment although twin studies and adoption studies have suggested a high level of heritability. It has been suggested that schizophrenia is a condition of complex inheritance, with many different major or minor
genesGênes is the name of a département of the First French Empire in present Italy. It was named after the city Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa. It was divided into the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
increasing risk. Some have suggested that risk factors for several genetic and other risk factors need to be present before a person becomes affected but this is still uncertain. The genes for schizophrenia and bipolar disorder as found in the recent genome wide association studies are largely separate but some do overlap between the two disorders Metaanalyses of
genetic linkageGenetic linkage occurs when particular genetic loci or alleles for genes are inherited jointly. Genetic loci on the same chromosome are physically close to one another and tend to stay together during meiosis, and are thus genetically linked. This is called autosomal linkage...
studies have produced consistent evidence of chromosomal regions increasing susceptibility, which interacts directly with the Disrupted in Schizophrenia 1 (DISC1) gene protein more recently the
zinc finger protein 804AZinc finger protein 804A or ZNF804A is a human protein that has a zinc finger in its structure.-Clinical significance:In a genome-wide study conducted in 2008, the rs1344706 SNP of the gene was shown to associate with schizophrenia...
. has been implicated as well as the chromosome 6 HLA region Schizophrenia has also been associated with rare deletions or duplications of tiny DNA sequences (known as
copy number variantsA copy number variation is a segment of DNA in which copy-number differences have been found by comparison of two or more genomes. The segment may range from one kilobase to several megabases in size. Humans ordinarily have two copies of each autosomal region, one per chromosome...
) disproportionately occurring within genes involved in neuronal signaling and brain development.
There is little doubt about the existence of a fecundity deficit in schizophrenia. Affected individuals have fewer children than the population as a whole. This reduction is of the order of 70% in males and 30% in females. The central genetic paradox of schizophrenia is why, if the disease is associated with a biological disadvantage, is this variation not selected out? To balance such a significant disadvantage, a substantial and universal advantage must exist. Thus far, all theories of a putative advantage have been disproved or remain unsubstantiated.
Prenatal
Causal factors are thought to initially come together in early neurodevelopment to increase the risk of later developing schizophrenia. One curious finding is that people diagnosed with schizophrenia are more likely to have been born in winter or spring, (at least in the
northern hemisphereThe Northern Hemisphere is the half of a planet that is north of the equator—the word hemisphere literally means 'half sphere'. It is also that half of the celestial sphere north of the celestial equator...
). There is now evidence that prenatal exposure to infections increases the risk for developing schizophrenia later in life, providing additional evidence for a link between in utero developmental pathology and risk of developing the condition.
Social
Living in an
urbanAn urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
environment has been consistently found to be a risk factor for schizophrenia. Social disadvantage has been found to be a risk factor, including poverty and migration related to social adversity, racial discrimination, family dysfunction, unemployment or poor housing conditions. Childhood experiences of abuse or trauma have also been implicated as risk factors for a diagnosis of schizophrenia later in life. Parenting is not held responsible for schizophrenia but unsupportive dysfunctional relationships may contribute to an increased risk.
Drug abuse
Although about half of all patients with schizophrenia abuse drugs or alcohol, a clear causal connection between drug use and schizophrenia has been difficult to prove. The two most often used explanations for this are "substance use causes schizophrenia" and "substance use is a consequence of schizophrenia", and they both may be correct. A 2007
meta-analysisIn statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. This is normally done by identification of a common measure of effect size, which is modelled using a form of meta-regression...
estimated that cannabis use is
statistically associatedIn statistics, an association is any relationship between two measured quantities that renders them statistically dependent. The term "association" refers broadly to any such relationship, whereas the narrower term "correlation" refers to a linear relationship between two quantities.There are many...
with a
dose-dependentThe dose-response relationship, or exposure-response relationship, describes the change in effect on an organism caused by differing levels of exposure to a stressor after a certain exposure time...
increase in risk of development of psychotic disorders, including schizophrenia. There is little evidence to suggest that other drugs including alcohol cause schizophrenia, or that psychotic individuals choose specific drugs to self-medicate; there is some support for the hypothesis that they use drugs to cope with unpleasant states such as depression, anxiety, boredom and loneliness. However, regarding
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
itself, it is well understood that
methamphetamineMethamphetamine also known as metamfetamine , dextromethamphetamine, methylamphetamine, N-methylamphetamine, and desoxyephedrine) is a psychostimulant and sympathomimetic drug. Methamphetamine enters the brain and triggers a cascading release of dopamine, serotonin and norepinephrine...
and
cocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system and an appetite suppressant...
use can result in methamphetamine- or cocaine-induced psychoses that present very similar symptomatology and may persist even when users remain abstinent.
Schizophrenia as a social construct
An approach broadly known as the
anti-psychiatryAnti-psychiatry usually refers to a configuration of groups and theories that emerged in the 1960s hostile to most of the fundamental assumptions and practices of psychiatry. Its igniting influences were Michel Foucault, R. D. Laing, Thomas Szasz and, in Italy, Franco Basaglia. The term was first...
movement, most active in the 1960s, opposes the orthodox medical view of schizophrenia as an illness. Psychiatrist
Thomas SzaszThomas Stephen Szasz ; born April 15, 1920 in Budapest, Hungary) is a psychiatrist and academic. Since 1990 he has been Professor Emeritus of Psychiatry at the State University of New York Health Science Center in Syracuse, New York...
argued that psychiatric patients are not ill, but rather individuals with unconventional thoughts and behavior that make society uncomfortable. He argues that society unjustly seeks to control them by classifying their behavior as an illness and forcibly treating them as a method of
social controlSocial control includes social mechanisms that regulate individual and group behavior, leading to conformity and compliances to the rules of a given society or social group. Many mechanisms of social control are cross-cultural, if only in the control mechanisms used to prevent the establishment of...
. According to this view, "schizophrenia" does not actually exist but is merely a form of
social constructionSocial constructionism and social constructivism are sociological theories of knowledge that consider how social phenomena develop in social contexts...
, created by society's concept of what constitutes normality and abnormality. Szasz has never considered himself to be "anti-psychiatry" in the sense of being against psychiatric treatment, but simply believes that treatment should be conducted between consenting adults, rather than imposed upon anyone against his or her will.
Other proposed causes
Psychiatrists R. D. Laing,
Silvano ArietiSilvano Arieti was a psychiatrist regarded in his time as one of the world’s foremost authorities on schizophrenia. He received his M.D. from the University of Pisa but left Italy soon after because of Mussolini's increasingly fascist racial policies...
,
Theodore LidzTheodore Lidz was an American psychiatrist best known for his articles and books on the causes of schizophrenia and on psychotherapy with schizophrenic patients...
and others have argued that the symptoms of what is called mental illness are comprehensible reactions to impossible demands that society and particularly family life places on some sensitive individuals. Laing, Arieti and Lidz were notable in valuing the
content of
psychoticPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
experience as worthy of interpretation, rather than considering it simply as a secondary and essentially meaningless marker of underlying psychological or neurological distress. Laing described eleven case studies of people diagnosed with schizophrenia and argued that the content of their actions and statements was meaningful and logical in the context of their family and life situations. In 1956, Palo Alto,
Gregory BatesonGregory Bateson was a British anthropologist, social scientist, linguist, visual anthropologist, semiotician and cyberneticist whose work intersected that of many other fields. Some of his most noted writings are to be found in his books, Steps to an Ecology of Mind and Mind and Nature...
and his colleagues
Paul WatzlawickPaul Watzlawick was an Austrian-American psychologist and philosopher. A theoretician in communication theory and radical constructivism, he has commented in the fields of family therapy and general psychotherapy...
,
Donald JacksonDon D. Jackson was an American psychiatrist best known for his pioneering work in family therapy.From 1947 to 1951 he studied under Harry Stack Sullivan....
, and
Jay HaleyJay Douglas Haley was a psychotherapist. He was one of the founding figures of brief and family therapy and a teacher, supervisor, and author in these disciplines.-Life and works:...
articulated a theory of schizophrenia, related to Laing's work, as stemming from
double bindA double bind is a dilemma in communication in which an individual receives two or more conflicting messages, with one message negating the other. This creates a situation in which a successful response to one message implicates a failed response to the other, so that the person will be...
situations where a person receives different or contradictory messages. Madness was therefore an expression of this distress and should be valued as a
catharticCatharsis is a Greek word meaning "purification","purging", "cleansing" or "clarification." It is derived from the infinitive verb of transliterated as kathairein "to purify, purge," and adjective katharos "pure or clean."-Dramaturgical uses:...
and transformative experience. In the books
Schizophrenia and the Family and
The Origin and Treatment of Schizophrenic Disorders Lidz and his colleagues explain their belief that parental behaviour can result in mental illness in children. Arieti's
Interpretation of Schizophrenia won the 1975 scientific
National Book AwardThe National Book Awards are among the most eminent literary prizes in the United States. Started in 1950, the awards are presented annually to American authors for literature published in the prior year, as well as lifetime achievement awards including the "Medal of Distinguished Contribution to...
in the United States.
The concept of schizophrenia as a result of civilization has been developed further by psychologist
Julian JaynesJulian Jaynes was an American psychologist, best known for his book The Origin of Consciousness in the Breakdown of the Bicameral Mind , in which he argued that ancient peoples did not access consciousness , but instead had their behavior directed by auditory hallucinations, which they...
in his 1976 book
The Origin of Consciousness in the Breakdown of the Bicameral Mind; he proposed that until the beginning of historic times, schizophrenia or a similar condition was the normal state of human consciousness. This would take the form of a "bicameral mind" where a normal state of low affect, suitable for routine activities, would be interrupted in moments of crisis by "mysterious voices" giving instructions, which early people characterized as interventions from the gods. Researchers into shamanism have speculated that in some cultures schizophrenia or related conditions may predispose an individual to becoming a shaman; the experience of having access to multiple realities is not uncommon in schizophrenia, and is a core experience in many shamanic traditions. Equally, the shaman may have the skill to bring on and direct some of the
altered states of consciousnessAn altered state of consciousness, , also named altered state of mind is any condition which is significantly different from a normal waking beta wave state. The expression was used as early as 1969 by Charles Tart and describes induced changes in one's mental state, almost always temporary...
psychiatrists label as illness.
PsychohistoriansPsychohistory is the study of the psychological motivations of historical events. It combines the insights of psychotherapy with the research methodology of the social sciences to understand the emotional origin of the social and political behavior of groups and nations, past and present...
, on the other hand, accept the psychiatric diagnoses. However, unlike the current
medical model of mental disordersBiological psychiatry, or biopsychiatry is an approach to psychiatry that aims to understand mental disorder in terms of the biological function of the nervous system...
they may argue that poor parenting in tribal societies causes the shaman's schizoid personalities. Commentators such as
Paul KurtzPaul Kurtz is Professor Emeritus of Philosophy at the State University of New York at Buffalo, but is best known for his prominent role in the United States skeptical community...
and others have endorsed the idea that major religious figures experienced psychosis, heard voices and displayed delusions of grandeur.
Psychiatrist
Tim CrowProfessor Tim Crow is a British psychiatrist and researcher. Much of his research is related to the causes of schizophrenia. He is the Honorary Director of the Prince of Wales International Centre for Research into Schizophrenia and Depression. He qualified at the Royal London Hospital in 1964 and...
has argued that schizophrenia may be the evolutionary price we pay for a left brain hemisphere specialization for
languageA language is a system for encoding and decoding information. In its most common use, the term refers to so-called "natural languages" — the forms of communication considered peculiar to humankind. In linguistics the term is extended to refer to the human cognitive facility of creating and using...
. Since psychosis is associated with greater levels of right brain hemisphere activation and a reduction in the usual left brain hemisphere dominance, our language abilities may have evolved at the cost of causing schizophrenia when this system breaks down. Other approaches have linked schizophrenia to psychological
dissociationDissociation is an unexpected partial or complete disruption of the normal integration of a person’s conscious or psychological functioning that cannot be easily explained by the person. Dissociation is a mental process that severs a connection to a person's thoughts, memories, feelings, actions,...
or states of awareness and identity understood from phenomenological and other perspectives.
There is an association of the disease with
brain-derived neurotrophic factorBrain-derived neurotrophic factor also known as BDNF is a protein which in humans is encoded by the BDNF gene. BDNF is a member of the "neurotrophin" family of growth factors – which are related to the canonical "Nerve Growth Factor", NGF...
(BDNF)..
Psychological
A number of non-causal psychological mechanisms have been implicated in the development and maintenance of schizophrenia.
Cognitive biasA cognitive bias is a person's tendency to make errors in judgment based on cognitive factors, and is a phenomenon studied in cognitive science and social psychology. Forms of cognitive bias include errors in statistical judgment, social attribution, and memory that are common to all human beings....
es that have been identified in those with a diagnosis or those at risk, especially when under stress or in confusing situations, include excessive attention to potential threats, jumping to conclusions, making external
attributionsAttribution is a concept in social psychology referring to how individuals explain causes of events, other's behavior, and their own behavior.- Types of attribution :...
, impaired reasoning about social situations and
mental statesTheory of mind is the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one's own...
, difficulty distinguishing inner speech from speech from an external source, and difficulties with early visual processing and maintaining concentration. Some cognitive features may reflect global neurocognitive deficits in
memoryIn psychology, memory is an organism's mental ability to store, retain, and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing the memory....
,
attentionAttention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. Attention has also been referred to as the allocation of processing resources...
,
problem-solvingProblem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...
, executive function or
social cognitionSocial cognition is the study of how people process social information, especially its encoding, storage, retrieval, and application to social situations. Social cognition’s focus on information processing has many affinities with its sister discipline, cognitive psychology...
, while others may be related to particular issues and experiences. Despite a common appearance of "blunted affect", recent findings indicate that many individuals diagnosed with schizophrenia are highly emotionally responsive, particularly to stressful or negative stimuli, and that such sensitivity may cause vulnerability to symptoms or to the disorder. Some evidence suggests that the content of delusional beliefs and psychotic experiences can reflect emotional causes of the disorder, and that how a person interprets such experiences can influence symptomatology. The use of "
safety behaviorsSafety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...
" to avoid imagined threats may contribute to the chronicity of delusions. Further evidence for the role of psychological mechanisms comes from the effects of therapies on symptoms of schizophrenia.
Neural
Studies using
neuropsychological testNeuropsychological tests are specifically designed tasks used to measure a psychological function known to be linked to a particular brain structure or pathway. They usually involve the systematic administration of clearly defined procedures in a formal environment...
s and brain imaging technologies such as
fMRIFunctional MRI or functional Magnetic Resonance Imaging is a type of specialized MRI scan. It measures the haemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...
and
PETPositron emission tomography is a nuclear medicine imaging technique which produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
to examine functional differences in brain activity have shown that differences seem to most commonly occur in the
frontal lobeThe frontal lobe is an area in the brain of mammals. It is located at the front of each cerebral hemisphere and positioned anterior to the parietal lobes and above and anterior to the temporal lobes...
s,
hippocampusThe hippocampus is a major component of the brains of humans and other mammals. It belongs to the limbic system and plays important roles in long-term memory and spatial navigation. Like the cerebral cortex, with which it is closely associated, it is a paired structure, with mirror-image halves in...
and
temporal lobeThe temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both the left and right hemispheres of the brain....
s. These differences have been linked to the neurocognitive deficits often associated with schizophrenia.
Particular focus has been placed upon the function of dopamine in the
mesolimbic pathwayThe mesolimbic pathway is one of the dopaminergic pathways in the brain. The pathway begins in the ventral tegmental area of the midbrain and connects to the limbic system via the nucleus accumbens, the amygdala, and the hippocampus as well as to the medial prefrontal cortex...
of the brain. This focus largely resulted from the accidental finding that a drug group which blocks dopamine function, known as the phenothiazines, could reduce psychotic symptoms. It is also supported by the fact that
amphetamineAmphetamine is a psychostimulant drug that is known to produce increased wakefulness and focus in association with decreased fatigue and appetite. Amphetamine is related to drugs such as methamphetamine and dextroamphetamine, which are a group of potent drugs that act by increasing levels of...
s, which triggers the release of dopamine may exacerbate the psychotic symptoms in schizophrenia. An influential theory, known as the
Dopamine hypothesis of schizophreniaThe dopamine hypothesis of schizophrenia or the dopamine hypothesis of psychosis is a model attributing symptoms of schizophrenia to a disturbed and hyperactive dopaminergic signal transduction. The model draws evidence from the observation that a large number of antipsychotics have...
, proposed that excess activation of
D2 receptorsDopamine receptor D2, also known as D2R, is a protein which in humans is encoded by the DRD2 gene.- Function :This gene encodes the D2 subtype of the dopamine receptor. This G-protein coupled receptor inhibits adenylyl cyclase activity...
was the cause of (the positive symptoms of) schizophrenia. Although postulated for about 20 years based on the D
2 blockade effect common to all antipsychotics, it was not until the mid-1990s that
PET-Medicine:* Patulous Eustachian tube, a medical disorder affecting the middle ear* Positron emission tomography, a medical imaging technique* Pre-eclampsia, a medical complication of pregnancy-Science:...
and SPET imaging studies provided supporting evidence. This explanation is now thought to be overly simplistic, partly because newer antipsychotic medication (called
atypical antipsychoticThe atypical antipsychotics are a group of antipsychotic drugs used to treat psychiatric conditions. Some atypical antipsychotics are FDA approved for use in the treatment of schizophrenia...
medication) can be equally effective as older medication (called
typical antipsychoticTypical antipsychotics are a class of antipsychotic drugs first developed in the 1950s and used to treat psychosis...
medication), but also affects
serotoninSerotonin is a monoamine neurotransmitter. It is found extensively in the gastrointestinal tract of animals, and about 80 to 90 percent of the human body's total serotonin is located in the enterochromaffin cells in the gut, where it is used to regulate intestinal movements...
function and may have slightly less of a
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
blocking effect.
Interest has also focused on the neurotransmitter glutamate and the reduced function of the
NMDA glutamate receptorThe NMDA receptor , a glutamate receptor, is the predominant molecular device for controlling synaptic plasticity and memory function....
in schizophrenia. This has largely been suggested by abnormally low levels of
glutamate receptorGlutamate receptors are transmembrane receptors located on the membranes of neuronal cells. These receptors bind the neurotransmitter glutamate.-Function:...
s found in postmortem brains of people previously diagnosed with schizophrenia and the discovery that the glutamate blocking drugs such as
phencyclidinePhencyclidine , also known as angel dust and other street names, is a recreational, dissociative drug formerly used as an anaesthetic agent, exhibiting hallucinogenic and neurotoxic effects...
and
ketamineKetamine is a drug used in human and veterinary medicine developed by Parke-Davis in 1962. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
can mimic the symptoms and cognitive problems associated with the condition. The fact that reduced glutamate function is linked to poor performance on tests requiring
frontal lobeThe frontal lobe is an area in the brain of mammals. It is located at the front of each cerebral hemisphere and positioned anterior to the parietal lobes and above and anterior to the temporal lobes...
and
hippocampalThe hippocampus is a major component of the brains of humans and other mammals. It belongs to the limbic system and plays important roles in long-term memory and spatial navigation. Like the cerebral cortex, with which it is closely associated, it is a paired structure, with mirror-image halves in...
function and that glutamate can affect
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
function, all of which have been implicated in schizophrenia, have suggested an important mediating (and possibly causal) role of glutamate pathways in schizophrenia. Positive symptoms fail however to respond to glutamatergic medication.
There have also been findings of differences in the size and structure of certain brain areas in schizophrenia. A 2006 metaanlaysis of MRI studies found that whole brain and hippocampal volume are reduced and that
ventricularThe ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord.-Components:The system comprises four ventricles:* right and left lateral ventricles* third ventricle...
volume is increased in patients with a first psychotic episode relative to healthy controls. The average volumetric changes in these studies are however close to the limit of detection by MRI methods, so it remains to be determined whether schizophrenia is a neurodegenerative process that begins at about the time of symptom onset, or whether it is better characterised as a neurodevelopmental process that produces abnormal brain volumes at an early age. In first episode psychosis typical antipsychotics like haloperidol were associated with significant reductions in gray matter volume, whereas atypical antipsychotics like olanzapine were not. Studies in non-human primates found gray and white matter reductions for both typical and atypical antipsychotics.
A 2009 meta-analysis of diffusion tensor imaging studies identified two consistent locations of fractional anisotropy reduction in schizophrenia. One region, in the left frontal lobe, is traversed by white matter tracts interconnecting the frontal lobe, thalamus and cingulate gyrus; the second region in the temporal lobe, is traversed by white matter tracts interconnecting the frontal lobe, insula, hippocampus–amygdala, temporal and occipital lobe. The authors suggest that two networks of white matter tracts may be affected in schizophrenia, with the potential for "disconnection" of the gray matter regions which they link. During fMRI studies, greater connectivity in the brain's
default networkThe default network is a network of brain regions that are active when the individual is not focused on the outside world and the brain is at wakeful rest. Also called the default mode network , default state network, or task-negative network , it is characterized by coherent neuronal oscillations...
and task-positive network has been observed in schizophrenic patients, and may reflect excessive orientation of attention to
introspectionIntrospection is the self-observation and reporting of conscious inner thoughts, desires and sensations. It is a conscious mental and usually purposive process relying on thinking, reasoning, and examining one's own thoughts, feelings, and, in more spiritual cases, one's soul...
and to extrospection, respectively. The greater anti-correlation between the two networks suggests excessive rivalry between the networks.
Screening and prevention
There are no reliable markers for the later development of schizophrenia although research is being conducted into how well a combination of genetic risk plus non-disabling psychosis-like experience predicts later diagnosis. People who fulfill the 'ultra high-risk mental state' criteria, that include a family history of schizophrenia plus the presence of transient or self-limiting psychotic experiences, have a 20–40% chance of being diagnosed with the condition after one year. The use of psychological treatments and medication has been found effective in reducing the chances of people who fulfill the 'high-risk' criteria from developing full-blown schizophrenia. However, the treatment of people who may never develop schizophrenia is controversial, in light of the side-effects of antipsychotic medication; particularly with respect to the potentially disfiguring
tardive dyskinesiaTardive dyskinesia is a variety of dyskinesia manifesting as a side effect of long-term or high-dose use of dopamine antagonists, usually antipsychotics. Other dopamine antagonists that can cause tardive dyskinesia are drugs for gastrointestinal disorders and neurological disorders...
and the rare but potentially lethal
neuroleptic malignant syndromeNeuroleptic malignant syndrome is a neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is associated with elevated creatine...
. The most widely used form of preventative health care for schizophrenia takes the form of public education campaigns that provide information on risk factors and early symptoms, with the aim to improve detection and provide treatment earlier for those experiencing delays. The new clinical approach
early intervention in psychosisEarly intervention in psychosis is a clinical approach to those experiencing symptoms of psychosis for the first time. It forms part of the new prevention paradigm for psychiatry and is leading to reform of mental health services, especially in the United Kingdom...
is a secondary prevention strategy to prevent further episodes and prevent the long term disability associated with schizophrenia.
Management
The concept of a cure as such remains controversial, as there is no consensus on the definition, although some criteria for the remission of symptoms have recently been suggested. The effectiveness of schizophrenia treatment is often assessed using standardized methods, one of the most common being the Positive and Negative Syndrome Scale (PANSS).
Management of symptoms and improving function is thought to be more achievable than a cure. Treatment was revolutionized in the mid-1950s with the development and introduction of
chlorpromazineChlorpromazine is the oldest typical antipsychotic. The molecular structure is 2-chloro-10--phenothiazine. It effectively treats schizophrenia, severe mania in people with bipolar disorder, and uncontrollable hiccups...
. A
recovery modelThe Recovery Model is an approach to mental disorder or substance dependence that emphasizes and supports each individual's potential for recovery...
is increasingly adopted, emphasizing hope, empowerment and social inclusion.
Hospitalization may occur with severe episodes of schizophrenia. This can be voluntary or (if mental health legislation allows it) involuntary (called civil or
involuntary commitmentInvoluntary commitment is the practice of using legal means or forms as part of a mental health law to commit a person to a mental hospital, insane asylum or psychiatric ward against their will and/or over their protests. In some juridictions , it was once known as the "restraint of the insane"...
). Long-term inpatient stays are now less common due to deinstitutionalization, although can still occur. Following (or in lieu of) a hospital admission, support services available can include drop-in centers, visits from members of a community mental health team or
Assertive Community TreatmentAssertive community treatment, or ACT, is a highly intensive and integrated approach for community mental health service delivery. ACT programs serve people whose symptoms of mental illness result in severe functional difficulties that interfere with their ability to achieve personally meaningful...
team, supported employment and patient-led support groups.
In many non-Western societies, schizophrenia may only be treated with more informal, community-led methods. Multiple international surveys by the World Health Organization over several decades have indicated that the outcome for people diagnosed with schizophrenia in non-Western countries is on average better there than for people in the West. Many clinicians and researchers suspect the relative levels of social connectedness and acceptance are the difference, although further
cross-cultural studiesCross-cultural comparisons take several forms. One is comparison of case studies, another is controlled comparison among variants of a common derivation, and a third is comparison within a sample of cases...
are seeking to clarify the findings.
Medication
The first line psychiatric treatment for schizophrenia is
antipsychoticAntipsychotics are a group of psychoactive drugs commonly but not exclusively used to treat psychosis, which is typified by schizophrenia, but can also be present in severe bipolar disorder, as well as many other conditions. Over time a wide range of antipsychotics have been developed...
medication. These can reduce the positive symptoms of psychosis. Most antipsychotics take around 7–14 days to have their main effect. Currently available antipsychotics fail, however, to significantly ameliorate the negative symptoms, and the improvements on cognition may be attributed to the practice effect.
The newer
atypical antipsychoticThe atypical antipsychotics are a group of antipsychotic drugs used to treat psychiatric conditions. Some atypical antipsychotics are FDA approved for use in the treatment of schizophrenia...
drugs are usually preferred for initial treatment over the older
typical antipsychoticTypical antipsychotics are a class of antipsychotic drugs first developed in the 1950s and used to treat psychosis...
, although they are expensive and are more likely to induce weight gain and
obesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
-related diseases. In 2008, results from a major randomized trial sponsored by the US National Institute of Mental Health (Clinical Antipsychotic Trials of Intervention Effectiveness, or CATIE) found that a representative first-generation antipsychotic, perphenazine, was as effective as and more cost-effective than several newer drugs (olanzapine, perphenazine, quetiapine, risperidone, or ziprasidone) taken for up to 18 months. The atypical antipsychotic which patients were willing to continue for the longest, olanzapine, was associated with considerable weight gain and risk of metabolic syndrome.
ClozapineClozapine is an antipsychotic medication used in the treatment of schizophrenia...
was most effective for people with a poor response to other drugs, but it had troublesome side effects. Because the trial excluded patients with
tardive dyskinesiaTardive dyskinesia is a variety of dyskinesia manifesting as a side effect of long-term or high-dose use of dopamine antagonists, usually antipsychotics. Other dopamine antagonists that can cause tardive dyskinesia are drugs for gastrointestinal disorders and neurological disorders...
, its relevance to these people is unclear.
The two classes of antipsychotics are generally thought equally effective for the treatment of the positive symptoms. Some researchers have suggested that the atypicals offer additional benefit for the negative symptoms and cognitive deficits associated with schizophrenia, although the clinical significance of these effects has yet to be established.
Because of their reportedly lower risk of side effects that affect mobility, atypical antipsychotics have been first-line treatment for early-onset schizophrenia for many years before certain drugs in this class were approved by the
Food and Drug AdministrationThe Food and Drug Administration is a Government agency of the United States Department of Health and Human Services and is responsible for regulating and supervising the safety of foods, tobacco products, dietary supplements, Medication drugs, vaccines, Biopharmaceutical, blood transfusion,...
for use in children and teenagers with schizophrenia. This advantage comes at the cost of an increased risk of
metabolic syndromeMetabolic syndrome is a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes. It affects one in five people, and prevalence increases with age...
and
obesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
, which is of concern in the context of long-term use begun at an early age. Especially in the case of children and teenagers who have schizophrenia, medication should be used in combination with individual therapy and family-based interventions.
Recent reviews have refuted the claim that atypical antipsychotics have fewer extrapyramidal side effects than typical antipsychotics, especially when the latter are used in low doses or when low potency antipsychotics are chosen.
Prolactin elevations have been reported in women with schizophrenia taking atypical antipsychotics. It remains unclear whether the newer antipsychotics reduce the chances of developing
neuroleptic malignant syndromeNeuroleptic malignant syndrome is a neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is associated with elevated creatine...
, a rare but serious and potentially fatal neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs.
Response of symptoms to medication is variable: treatment-resistant schizophrenia is a term used for the failure of symptoms to respond satisfactorily to at least two different antipsychotics. Patients in this category may be prescribed
clozapineClozapine is an antipsychotic medication used in the treatment of schizophrenia...
, a medication of superior effectiveness but several potentially lethal side effects including
agranulocytosisAgranulocytosis, also known as agranulosis, is an acute condition involving a severe and dangerous leukopenia, most commonly of neutrophils, causing a neutropenia in the circulating blood. It represents a severe lack of one major class of infection-fighting white blood cells...
and
myocarditisIn medicine , myocarditis is inflammation of heart muscle . It resembles a heart attack but coronary arteries are not blocked....
. Clozapine may have the additional benefit of reducing propensity for substance abuse in schizophrenic patients. For other patients who are unwilling or unable to take medication regularly, long-acting depot preparations of antipsychotics may be given every two weeks to achieve control. The United States and Australia are two countries with
lawsOutpatient commitment refers to mental health law which allows the compulsory, community-based treatment of individuals with mental illness.In the United States the term "assisted outpatient treatment" is often used and refers to the practice of courts requiring those it has found to be mentally...
allowing the forced administration of this type of medication on those who refuse but are otherwise stable and living in the community. At least one study suggested that in the longer-term some individuals may do better not taking antipsychotics.
A 2003 review of four randomized controlled trials of
EPAEicosapentaenoic acid is an omega-3 fatty acid. In physiological literature, it is given the name 20:5. It also has the trivial name timnodonic acid...
(an
omega-3 fatty acidn−3 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid.Important nutritionally essential n−3 fatty acids are: α-linolenic acid , eicosapentaenoic acid...
) vs. placebo as adjunctive treatment for schizophrenia found that two of the trials detected a significant improvement on positive and negative symptoms, and suggested that EPA may be an effective adjunct to antipsychotics. The most recent
meta-analysisIn statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. This is normally done by identification of a common measure of effect size, which is modelled using a form of meta-regression...
(2006) failed however to find a significant effect. A 2007 review found that studies of omega-3 fatty acids in schizophrenia, despite being mostly of high quality, have produced inconsistent results and small
effect sizeIn statistics, an effect size is a measure of the strength of the relationship between two variables in a statistical population, or a sample-based estimate of that quantity...
s of doubtful clinical significance.
Psychological and social interventions
PsychotherapyPsychotherapy or personal counseling with a psychotherapist, is an intentional interpersonal relationship used by trained psychotherapists to aid a client or patient in problems of living.It aims to increase the individual's sense of their own well-being...
is also widely recommended and used in the treatment of schizophrenia, although services may often be confined to pharmacotherapy because of reimbursement problems or lack of training.
Cognitive behavioral therapy (CBT) is used to target specific symptoms and improve related issues such as
self-esteemSelf-esteem is a term used in psychology to reflect a person's overall evaluation or appraisal of his or her own worth.Self-esteem encompasses beliefs and emotions...
, social functioning, and insight. Although the results of early trials were inconclusive as the therapy advanced from its initial applications in the mid 1990s, more recent reviews clearly show CBT is an effective treatment for the psychotic symptoms of schizophrenia
Another approach is cognitive remediation therapy, a technique aimed at remediating the neurocognitive deficits sometimes present in schizophrenia. Based on techniques of neuropsychological rehabilitation, early evidence has shown it to be cognitively effective, with some improvements related to measurable changes in brain activation as measured by fMRI. A similar approach known as cognitive enhancement therapy, which focuses on social cognition as well as neurocognition, has shown efficacy.
Family therapyFamily therapy, also referred to as couple and family therapy and family systems therapy, is a branch of psychotherapy that works with families and couples in intimate relationships to nurture change and development. It tends to view change in terms of the systems of interaction between family...
or education, which addresses the whole family system of an individual with a diagnosis of schizophrenia, has been consistently found to be beneficial, at least if the duration of intervention is longer-term. Aside from therapy, the impact of schizophrenia on families and the burden on carers has been recognized, with the increasing availability of self-help books on the subject. There is also some evidence for benefits from social skills training, although there have also been significant negative findings. Some studies have explored the possible benefits of music therapy and other creative therapies.
The
SoteriaSoteria is a community service that provides a space for people experiencing mental distress or crisis. Based on a recovery model, common elements of the Soteria approach include primarily non-medical staffing; preserving resident's personal power, social networks, and communal responsibilities;...
model is alternative to inpatient hospital treatment using a minimal medication approach. It is described as a
milieuThe social environment , also known as the milieu, is the identical or similar social positions and social roles as a whole that influence the individuals of a group. The social environment of an individual is the culture that he or she was educated and/or lives in, and the people and institutions...
-therapeutic recovery method, characterized by its founder as "the 24 hour a day application of interpersonal phenomenologic interventions by a nonprofessional staff, usually without neuroleptic drug treatment, in the context of a small, homelike, quiet, supportive, protective, and tolerant social environment." Although research evidence is limited, a 2008 systematic review found the programme equally as effective as treatment with medication in people diagnosed with first and second episode schizophrenia.
Other
Electroconvulsive therapyElectroconvulsive therapy , also known as electroshock, is a well-established, albeit controversial, psychiatric treatment in which seizures are electrically induced in anesthetized patients for therapeutic effect...
is not considered a
first line treatmentA first-line treatment or first-line therapy is a medical therapy recommended for the initial treatment of a disease, sign or symptom, usually on the basis of empirical evidence for its efficacy.- Overview :...
but may be prescribed in cases where other treatments have failed. It is more effective where symptoms of catatonia are present, and is recommended for use under
NICEThe National Institute for Health and Clinical Excellence or NICE is a special health authority of the National Health Service in England and Wales...
guidelines in the UK for catatonia if previously effective, though there is no recommendation for use for schizophrenia otherwise.
PsychosurgeryPsychosurgery is a subset of neurosurgery intended to modulate the performance of the brain, and thus effect changes in cognition, with the intent to treat or alleviate severe mental illness...
has now become a rare procedure and is not a recommended treatment.
Service-user led movements have become integral to the recovery process in Europe and the United States; groups such as the
Hearing Voices NetworkThe Hearing Voices Network is a self-help user-run organization for people who 'hear voices'. Although members may have a psychiatric diagnosis, the group promotes an alternative approach, where voices are not necessarily seen as signs of mental illness....
and the
Paranoia NetworkThe Paranoia Network, founded in November 2003, is a self-help user-run organisation in Sheffield, England, for people who have paranoid or delusional beliefs....
have developed a self-help approach that aims to provide support and assistance outside the traditional medical model adopted by mainstream psychiatry. By avoiding framing personal experience in terms of criteria for
mental illnessA mental disorder or mental illness is a psychological or behavioral pattern that occurs in an individual and is thought to cause distress or disability that is not expected as part of normal development or culture. The recognition and understanding of mental disorders has changed over time and...
or
mental healthMental health is a term used to describe either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life...
, they aim to destigmatize the experience and encourage individual responsibility and a positive self-image. Partnerships between hospitals and consumer-run groups are becoming more common, with services working toward remediating social withdrawal, building social skills and reducing rehospitalization.
Alternative medical treatments
Orthomolecular psychiatryOrthomolecular medicine, or megavitamin therapy, is a form of complementary and alternative medicine that seeks to prevent or treat diseases with nutrients prescribed as dietary supplements or derived from diets...
considers schizophrenia to be a group of disorders, some of which can be treated with megadoses of nutrients, such as
NiacinNiacin, also known as vitamin B
3 or nicotinic acid, is a water-soluble vitamin. It is an organic compound with the molecular formula C
6H
5NO
2. It is a derivative of pyridine, with a carboxyl group at the 3-position...
(vitamin B-3). Proponents of orthomolecular psychiatry claim that an adverse reaction to
glutenGluten is a composite of the proteins gliadin and glutenin. These exist, conjoined with starch, in the endosperms of some grass-related grains, notably wheat, rye, and barley. Gliadin and glutenin comprise about 80% of the protein contained in wheat seed. Being insoluble in water, they can be...
is involved in the etiology of some cases. This theory—discussed by one author in three British journals in the 1970s—is unproven. A 2006 literature review suggests that gluten may be a factor for patients with celiac disease and for a subset of patients afflicted with schizophrenia, but that further study is needed to conclusively confirm such a link. In a 2004 Israeli study, anti-gluten antibodies were measured in 50 patients with schizophrenia and a matched control group. All antibody tests in both groups were negative leading to the conclusion that "it is unlikely that there is an association between gluten sensitivity and schizophrenia". Some researchers suggest that dietary and nutritional treatments may hold promise in the treatment of schizophrenia.
Course
Coordinated by the
World Health OrganizationThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health...
and published in 2001, The International Study of Schizophrenia (ISoS) was a long-term follow-up study of 1633 individuals diagnosed with schizophrenia around the world. The striking difference in course and outcomes was noted; a half of those available for follow-up had a favourable outcome and 16% had a delayed recovery after an early unremitting course. More usually, the course in the first two years predicted the long-term course. Early social intervention was also related to a better outcome. The findings were held as important in moving patients, carers and clinicians away from the prevalent belief of the chronic nature of the condition. A review of major
longitudinal studiesA longitudinal study is a correlational research study that involves repeated observations of the same items over long periods of time — often many decades. It is a type of observational study. Longitudinal studies are often used in psychology to study developmental trends across the life...
in North America noted this variation in outcomes, although outcome was on average worse than for other psychotic and psychiatric disorders. A moderate number of patients with schizophrenia were seen to remit and remain well; the review raised the question that some may not require maintenance medication.
A clinical study using strict recovery criteria (concurrent remission of positive and negative symptoms and adequate social and vocational functioning continuously for two years) found a recovery rate of 14% within the first five years. A 5-year community study found that 62% showed overall improvement on a composite measure of clinical and functional outcomes.
World Health OrganizationThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health...
studies have noted that individuals diagnosed with schizophrenia have much better long-term outcomes in developing countries (India, Colombia and Nigeria) than in developed countries (United States, United Kingdom, Ireland, Denmark, Czech Republic, Slovakia, Japan, and Russia), despite antipsychotic drugs not being widely available.
Defining recovery
Rates are not always comparable across studies because exact definitions of remission and recovery have not been widely established. A "Remission in Schizophrenia Working Group" has proposed standardized remission criteria involving "improvements in core signs and symptoms to the extent that any remaining symptoms are of such low intensity that they no longer interfere significantly with behavior and are below the threshold typically utilized in justifying an initial diagnosis of schizophrenia". Standardized recovery criteria have also been proposed by a number of different researchers, with the stated DSM definitions of a "complete return to premorbid levels of functioning” or "complete return to full functioning" seen as inadequate, impossible to measure, incompatible with the variability in how society defines normal psychosocial functioning, and contributing to self-fulfilling pessimism and stigma. Some mental health professionals may have quite different basic perceptions and concepts of recovery than individuals with the diagnosis, including those in the consumer/survivor movement. One notable limitation of nearly all the research criteria is failure to address the person's own evaluations and feelings about their life. Schizophrenia and recovery often involve a continuing loss of self-esteem, alienation from friends and family, interruption of school and career, and social stigma, "experiences that cannot just be reversed or forgotten". An increasingly influential
modelThe Recovery Model is an approach to mental disorder or substance dependence that emphasizes and supports each individual's potential for recovery...
defines recovery as a process, similar to being "in recovery" from drug and alcohol problems, and emphasizes a personal journey involving factors such as hope, choice, empowerment, social inclusion and achievement.
Predictors
Several factors have been associated with a better overall prognosis: Being female, rapid (vs. insidious) onset of symptoms, older age of first episode, predominantly positive (rather than negative) symptoms, presence of mood symptoms, and good pre-illness functioning. The strengths and internal resources of the individual concerned, such as determination or
psychological resilienceResilience in psychology is the positive capacity of people to cope with stress and catastrophe. It is also used to indicate a characteristic of resistance to future negative events. In this sense "resilience" corresponds to cumulative "protective factors" and is used in opposition to cumulative...
, have also been associated with better prognosis. The attitude and level of support from people in the individual's life can have a significant impact; research framed in terms of the negative aspects of this—the level of critical comments, hostility, and intrusive or controlling attitudes, termed high '
Expressed emotionExpressed emotion , a qualitative measure of the 'amount' of emotion displayed, typically in the family setting, usually by a family or care takers....
'—has consistently indicated links to relapse. Most research on predictive factors is correlational in nature, however, and a clear cause-and-effect relationship is often difficult to establish.
Mortality
In a study of over 168,000 Swedish citizens undergoing psychiatric treatment, schizophrenia was associated with an average life expectancy of approximately 80–85% of that of the general population; women were found to have a slightly better life expectancy than men, and a diagnosis of schizophrenia was associated with an overall better life expectancy than
substance abuseAlthough the term substance can refer to any physical matter, substance abuse has come to refer to the overindulgence in and dependence of a drug or other chemical leading to effects that are detrimental to the individual's physical and mental health, or the welfare of others.]The disorder is...
,
personality disorderPersonality disorders, formerly referred to as character disorders, are a class of personality types which deviate from the contemporary expectations of a society....
,
heart attackMyocardial infarction or acute myocardial infarction , commonly known as a heart attack, is the interruption of blood supply to part of the heart, causing some heart cells to die...
and
strokeA stroke is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by thrombosis or embolism or due to a hemorrhage...
. Other identified factors include smoking, poor diet, little exercise and the negative health effects of psychiatric drugs.
There is a higher than average
suicideSuicide is the intentional killing of one's self. Many dictionaries also note the metaphorical sense of "willful destruction of one's self-interest"...
rate associated with schizophrenia. This has been cited at 10%, but a more recent analysis of studies and statistics revises the estimate at 4.9%, most often occurring in the period following onset or first hospital admission. Several times more attempt suicide. There are a variety of reasons and risk factors.
Violence
The relationship between violent acts and schizophrenia is a contentious topic. Current research indicates that the percentage of people with schizophrenia who commit violent acts is higher than the percentage of people without any disorder, but lower than is found for disorders such as
alcoholismAlcoholism is a term with multiple and sometimes conflicting definitions. In common and historic usage, alcoholism is any condition that results in the continued consumption of alcoholic beverages, despite health problems and negative social consequences...
, and the difference is reduced or not found in same-neighbourhood comparisons when related factors are taken into account, notably sociodemographic variables and substance misuse. Studies have indicated that 5% to 10% of those charged with murder in Western countries have a schizophrenia spectrum disorder.
The occurrence of
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
in schizophrenia has sometimes been linked to a higher risk of violent acts. Findings on the specific role of delusions or hallucinations have been inconsistent, but have focused on delusional jealousy, perception of threat and command hallucinations. It has been proposed that a certain type of individual with schizophrenia may be most likely to offend, characterized by a history of educational difficulties, low IQ, conduct disorder, early-onset substance misuse and offending prior to diagnosis.
Individuals with a diagnosis of schizophrenia are often the victims of violent crime—at least 14 times more often than they are perpetrators. Another consistent finding is a link to substance misuse, particularly alcohol, among the minority who commit violent acts. Violence by or against individuals with schizophrenia typically occurs in the context of complex social interactions within a family setting, and is also an issue in clinical services and in the wider community.
Epidemiology
Schizophrenia occurs equally in males and females, although typically appears earlier in men—the peak ages of onset are 20–28 years for males and 26–32 years for females. Onset in childhood is much rarer, as is onset in middle- or old age. The lifetime prevalence of schizophrenia—the proportion of individuals expected to experience the disease at any time in their lives—is commonly given at 1%. However, a 2002
systematic reviewA systematic review is a literature review focused on a single question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
of many studies found a lifetime prevalence of 0.55%. Despite the received wisdom that schizophrenia occurs at similar rates worldwide, its prevalence varies across the world, within countries, and at the local and neighbourhood level. One particularly stable and replicable finding has been the association between living in an
urbanUrbanization is the physical growth of urban areas from rural areas as a result of population immigration to an existing urban area. Effects include change in density and administration services. While the exact definition and population size of urbanized areas varies amongdifferent countries,...
environment and schizophrenia diagnosis, even after factors such as
drug useDrugs can be used in many different ways, as detailed below.-Medication:People can use drugs to relieve pain or discomfort or to cure or prevent disease.-Recreational drug use:...
,
ethnic groupAn ethnic group is a group of humans whose members identify with each other, through a common heritage that is real or presumed.Ethnic identity is further marked by the researcher Seng Yang in the recognition from others of a group's distinctiveness and the recognition of common cultural,...
and size of social group have been controlled for. Schizophrenia is known to be a major cause of
disabilityDisability is defined by the Americans with Disabilities Act of 1990 as "a physical or mental impairment that substantially limits one or more major life activities."...
. In a 1999 study of 14 countries, active
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
was ranked the third-most-disabling condition after
quadriplegiaQuadriplegia, also known as tetraplegia, is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all of their limbs and torso; paraplegia is similar but does not affect the arms...
and
dementiaDementia is a serious cognitive disorder. It may be static, the result of a unique global brain injury or progressive, resulting in long-term decline in cognitive function due to damage or disease in the body beyond what might be expected from normal aging...
and ahead of
paraplegiaParaplegia is an impairment in motor and/or sensory function of the lower extremities. It is usually the result of spinal cord injury or a congenital condition such as spina bifida which affects the neural elements of the spinal canal. The area of the spinal canal which is affected in paraplegia is...
and
blindnessBlindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
.
History
Accounts of a schizophrenia-like
syndromeIn medicine and psychology, the term syndrome refers to the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one feature alerts the physician to the presence of the others...
are thought to be rare in the historical record prior to the 1800s, although reports of irrational, unintelligible, or uncontrolled behavior were common. There has been an interpretation that brief notes in the Ancient Egyptian
Ebers papyrusThe Ebers Papyrus of about 1550 BC is among the most important medical papyri of ancient Egypt. It is also commonly called Papyrus Ebers[ at WorldCat.] . It is one of the two oldest preserved medical documents anywhere, the other main source being the Edwin Smith papyrus...
may imply schizophrenia, but other reviews have not suggested any connection. A review of
ancient GreekAncient Greece is the civilisation belonging to the period of Greek history lasting from the Greek Dark Ages ca. 1100 BC and the Dorian invasion, to 146 BC and the Roman conquest of Greece after the Battle of Corinth. It is generally considered to be the seminal culture which provided the...
and
RomanAncient Rome was a civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC. Located along the Mediterranean Sea, it became one of the largest empires in the ancient world....
literature indicated that although
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
was described, there was no account of a condition meeting the criteria for schizophrenia. Bizarre psychotic beliefs and behaviors similar to some of the symptoms of schizophrenia were reported in
Arabic medicalIn the history of medicine, Islamic medicine or Arabic medicine refers to medicine developed in the medieval Islamic civilization and written in Arabic, the lingua franca of the Islamic civilization. Despite these names, a significant number of scientists during this period were not Arab...
and
psychological literatureIslamic psychology or Ilm-al Nafsiat refers to the study of the Nafs in the Islamic world, particularly during the Islamic Golden Age as well as modern times , and is related to psychology, psychiatry and the neurosciences.Some of the advances in medieval Islamic...
during the
Middle AgesThe Middle Ages of European history is a period of European history covering roughly a millennium in the 5th century through 16th centuries. More specific starting and ending points are sometimes adopted by scholars to suit their respective specializations or current focus...
. In
The Canon of MedicineThe Canon of Medicine is a 14-volume medical encyclopedia written by Islamic scientist and physician Ibn Sīnā...
, for example,
Avicenna, known as Abū Alī Sīnā or Ibn Sīnā , and commonly known in English by his Latinized name Avicenna , was a Persian polymath and the foremost physician and philosopher of his time...
described a condition somewhat resembling the symptoms of schizophrenia which he called
Junun Mufrit (severe madness), which he distinguished from other forms of madness (
Junun) such as
maniaMania is a severe medical condition characterized by extremely elevated mood, energy, unusual thought patterns and sometimes psychosis...
,
rabiesRabies is a viral neuroinvasive disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal but occasionally by other forms of contact...
and
manic depressiveBipolar disorder, also known as manic depressive disorder, manic depression or bipolar affective disorder, is a serious mental disorder that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated mood clinically referred to as mania or, if...
psychosis. However, no condition resembling schizophrenia was reported in
Şerafeddin SabuncuoğluŞerafeddin Sabuncuoğlu was a medieval Ottoman surgeon and physician.Sabuncuoğlu was the author of the Cerrahiyyetu'l-Haniyye , the first illustrated surgical atlas, and the Mücerrebname .The Cerrahiyyetu'l-Haniyye was the first surgical atlas and the last...
's
Imperial Surgery, a major Islamic medical textbook of the 15th century. Given limited historical evidence, schizophrenia (as prevalent as it is today) may be a modern phenomenon, or alternatively it may have been obscured in historical writings by related concepts such as
melancholiaMelancholia , also lugubriousness, from the Latin lugere, to mourn; moroseness, from the Latin morosus, self-willed, fastidious habit; wistfulness, from old English wist: intent, or saturnine, , in contemporary usage, is a mood disorder of non-specific depression,...
or
maniaMania is a severe medical condition characterized by extremely elevated mood, energy, unusual thought patterns and sometimes psychosis...
.
A detailed case report in 1797 concerning
James Tilly MatthewsJames Tilly Matthews was a London tea broker, originally from Wales, who was committed to the Bethlem psychiatric hospital in 1797, and is considered to be the first fully documented case of paranoid schizophrenia.-Voyage to France:...
, and accounts by Phillipe Pinel published in 1809, are often regarded as the earliest cases of schizophrenia in the medical and psychiatric literature. Schizophrenia was first described as a distinct syndrome affecting teenagers and young adults by
Bénédict MorelBénédict Augustin Morel , was a French physician born in Vienna, Austria. He was an influential figure in the field of psychiatry during the mid-19th century....
in 1853, termed
démence précoce (literally 'early dementia'). The term
dementia praecoxDementia praecox refers to a chronic, deteriorating psychotic disorder characterized by rapid cognitive disintegration, usually beginning in the late teens or early adulthood. It is a term first used in 1891 in this Latin form by Arnold Pick , a professor of psychiatry at the German branch of...
was used in 1891 by
Arnold PickArnold Pick was a German neurologist and psychiatrist. He is known for identifying the clinical syndrome of Pick's Disease and the Pick bodies that are characteristic of the disorder. He was the first to name reduplicative paramnesia. He was also to use the term dementia praecox .- External links...
to in a case report of a psychotic disorder. In 1893
Emil KraepelinEmil Kraepelin was a German psychiatrist. The Encyclopedia of Psychology by H. J. Eysenck identifies him as the founder of contemporary scientific psychiatry, as well as of psychopharmacology and psychiatric genetics. Kraepelin believed the chief origin of psychiatric disease to be biological...
introduced a broad new distinction in the
classification of mental disordersThe classification of mental disorders, also known as psychiatric nosology or taxonomy, is a key aspect of psychiatry and other mental health professions and an important issue for consumers and providers of mental health services...
between
dementia praecoxDementia praecox refers to a chronic, deteriorating psychotic disorder characterized by rapid cognitive disintegration, usually beginning in the late teens or early adulthood. It is a term first used in 1891 in this Latin form by Arnold Pick , a professor of psychiatry at the German branch of...
and
mood disorderA mood disorder is the term given for a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
(termed manic depression and including both unipolar and bipolar depression). Kraepelin believed that
dementia praecox was primarily a disease of the brain, and particularly a form of
dementiaDementia is a serious cognitive disorder. It may be static, the result of a unique global brain injury or progressive, resulting in long-term decline in cognitive function due to damage or disease in the body beyond what might be expected from normal aging...
, distinguished from other forms of dementia, such as
Alzheimer's diseaseAlzheimer's disease , also called Alzheimer disease, Senile Dementia of the Alzheimer Type or simply Alzheimer's, is the most common form of dementia. This incurable, degenerative, and terminal disease was first described by German psychiatrist and neuropathologist Alois Alzheimer in 1906 and was...
, which typically occur later in life. Kraepelin's classification slowly gained acceptance. There were objections to the use of the term "dementia" despite cases of recovery, and some defence of diagnoses it replaced such as adolescent insanity.
The word
schizophrenia—which translates roughly as "splitting of the mind" and comes from the
GreekAncient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...
roots
schizein (σχίζειν, "to split") and
phrēn,
phren- (φρήν, φρεν-, "
mindMind is the aspect of intellect and consciousness experienced as combinations of thought, perception, memory, emotion, will and imagination, including all unconscious cognitive processes. The term is often used to refer, by implication, to the thought processes of reason. Mind manifests itself...
")—was coined by
Eugen BleulerPaul Eugen Bleuler was a Swiss psychiatrist most notable for his contributions to the understanding of mental illness and coining the term schizophrenia....
in 1908 and was intended to describe the separation of function between
personalityPersonality psychology is a branch of psychology that studies personality and individual differences.Its areas of focus include:* Constructing a coherent picture of a person and his or her major psychological processes...
,
thinkingThought and thinking are mental forms and processes, respectively . Thinking allows beings to model the world and to deal with it according to their objectives, plans, ends and desires. Words referring to similar concepts and processes include cognition, sentience, consciousness, idea, and...
,
memoryIn psychology, memory is an organism's mental ability to store, retain, and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing the memory....
, and
perceptionIn philosophy, psychology, and the cognitive sciences, perception is the process of attaining awareness or understanding of sensory information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was predicted that building perceiving machines would take about a decade,...
. Bleuler described the main symptoms as 4
As: flattened Affect
, Autism
, impaired Association
of ideas and Ambivalence
. Bleuler realized that the illness was not a dementiaDementia is a serious cognitive disorder. It may be static, the result of a unique global brain injury or progressive, resulting in long-term decline in cognitive function due to damage or disease in the body beyond what might be expected from normal aging...
as some of his patients improved rather than deteriorated and hence proposed the term schizophrenia instead.
The term schizophrenia
is commonly misunderstood to mean that affected persons have a "split personality". Although some people diagnosed with schizophrenia may hear voices and may experience the voices as distinct personalities, schizophrenia does not involve a person changing among distinct multiple personalities. The confusion arises in part due to the meaning of Bleuler's term schizophrenia (literally "split" or "shattered mind"). The first known misuse of the term to mean "split personality" was in an article by the poet
T. S. EliotThomas Stearns Eliot, OM , was a poet, playwright, and literary critic. He received the Nobel Prize in Literature in 1948. Among his most famous writings are The Love Song of J...
in 1933.
In the first half of the twentieth century schizophrenia was considered to be a hereditary defect, and sufferers were subject to
eugenicsEugenics is the study and practice of selective breeding applied to humans, with the aim of improving the species. Widely popular in the early decades of the 20th century, after having become associated with the Holocaust, it has largely fallen into disrepute.- Overview :As a social movement...
in many countries. Hundreds of thousands were
sterilizedSterilization is a surgical technique leaving a male or female unable to reproduce. It is a method of birth control. For non-surgical causes of sterility, see infertility.Common sterilization methods include:...
, with or without consent—the majority in
Nazi GermanyNazi Germany and the Third Reich are the common English names for Germany between 1933 and 1945, while it was led by Adolf Hitler and the National Socialist German Worker's Party . The name Third Reich refers to the state as the successor to the Holy Roman Empire of the Middle Ages and the German...
, the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and
ScandinaviaScandinavia is a geographical region in northern Europe that includes, and is named after, the Scanian Province. It consists of the kingdoms of Norway, Sweden, and Denmark...
n countries. Along with other people labeled "mentally unfit", many diagnosed with schizophrenia were murdered in the Nazi "
Action T4Action T4 was a program, also called Euthanasia Program, in Nazi Germany spanning October 1939 until August 1941, during which physicians killed 70,273 people specified in Hitler's secret memo of September 1, 1939 as suffering patients "judged incurably sick, by critical medical examination", but...
" program.
In the early 1970s, the diagnostic criteria for schizophrenia was the subject of a number of controversies which eventually led to the operational criteria used today. It became clear after the 1971 US-UK Diagnostic Study that schizophrenia was diagnosed to a far greater extent in America than in Europe. This was partly due to looser diagnostic criteria in the US, which used the DSM-II manual, contrasting with Europe and its ICD-9.
David Rosenhan'sDavid L. Rosenhan is an American psychologist. He is best known for the Rosenhan experiment.Rosenhan received his Bachelor of Arts degree from Yeshiva University...
1972 study, published in the journal
ScienceScience is the academic journal of the American Association for the Advancement of Science and is considered one of the world's most prestigious scientific journals. The peer-reviewed journal, first published in 1880 is circulated weekly and has a print subscriber base of around 130,000...
under the title On being sane in insane placesThe Rosenhan experiment was a famous experiment into the validity of psychiatric diagnosis conducted by David Rosenhan in 1963. It was published in the journal Science under the title "On being sane in insane places."...
, concluded that the diagnosis of schizophrenia in the US was often subjective and unreliable. These were some of the factors in leading to the revision not only of the diagnosis of schizophrenia, but the revision of the whole DSM manual, resulting in the publication of the DSM-III in 1980. Since the 1970s more than 40 diagnostic criteria for schizophrenia have been proposed and evaluated.
In the
Soviet UnionThe Union of Soviet Socialist Republics was a constitutionally socialist state that existed in Eurasia from 1922 to 1991. The name is a translation of the , tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik, abbreviated СССР, SSSR. The common short name is Soviet Union, from , Sovetskiy Soyuz...
the diagnosis of schizophrenia has also been used for political purposes. The prominent Soviet psychiatrist
Andrei SnezhnevskyAndrei Snezhnevsky was a Soviet psychiatrist notorious for expanding the diagnostic criteria for schizophrenia, a step that allowed for arbitrary labeling of political dissidents as having sluggishly progressing schizophrenia...
created and promoted an additional sub-classification of
sluggishly progressing schizophreniaSluggishly progressing schizophrenia or sluggish schizophrenia was a category of schizophrenia diagnosed by psychiatrists in the Soviet Union. At the time, Western psychiatry recognized only four types of schizophrenia: catatonic, hebephrenic, paranoid, and simple...
. This diagnosis was used to discredit and expeditiously imprison political dissidents while dispensing with a potentially embarrassing trial. The practice was exposed to Westerners by a number of Soviet dissidents, and in 1977 the
World Psychiatric AssociationThe World Psychiatric Association is an international umbrella organisation of psychiatric societies. Originally created to produce world psychiatric congresses, it has evolved to hold regional meetings, to promote professional education and to set ethical, scientific and treatment standards for...
condemned the Soviet practice at the Sixth World Congress of Psychiatry. Rather than defending his claim that a latent form of schizophrenia caused dissidents to oppose the regime, Snezhnevsky broke all contact with the West in 1980 by resigning his honorary positions abroad.
Stigma
Social stigmaSocial stigma is severe social disapproval of personal characteristics or beliefs that are perceived to be against cultural norms. Stigma is often based on ignorance, irrational or unfounded fears, mass hysteria, lack of education, or a lack of information pertaining to a particular person or group...
has been identified as a major obstacle in the recovery of patients with schizophrenia. In a large, representative sample from a 1999 study, 12.8% of Americans believed that individuals with schizophrenia were "very likely" to do something violent against others, and 48.1% said that they were "somewhat likely" to. Over 74% said that people with schizophrenia were either "not very able" or "not able at all" to make decisions concerning their treatment, and 70.2% said the same of money management decisions. The perception of individuals with psychosis as violent has more than doubled in prevalence since the 1950s, according to one meta-analysis.
In order to reduce stigma, in 2002 the Japanese Society of Psychiatry and Neurology changed the term for schizophrenia from Seishin-Bunretsu-Byo
精神分裂病 (mind-split-disease) to Tōgō-shitchō-shō
統合失調症 (integration disorderTōgō-shitchō-shō or integration disorder is a Japanese psychiatric diagnosis that replaced the previous diagnostic category of Seishin Bunretsu Byo which was equivalent to the DSM-IV or ICD-10 diagnosis of schizophrenia....
). The new name was inspired by the bio-psychosocial model, and it increased the percentage of cases in which patients were informed of the diagnosis from 36.7% to 69.7% over three years.
Iconic cultural depictions
The book and film A Beautiful MindA Beautiful Mind is a 2001 American film based on the life of John Forbes Nash, a Nobel Laureate in Economics. The film was directed by Ron Howard and written by Akiva Goldsman. It was inspired by a bestselling, Pulitzer Prize-nominated 1998 book of the same name by Sylvia Nasar...
chronicled the life of John Forbes NashJohn Forbes Nash Jr., Ph.D. is an American mathematician whose works in game theory, differential geometry, and partial differential equations have provided insight into the forces that govern chance and events inside complex systems in daily life...
, a Nobel PrizeThe Nobel Prize is a Sweden-based international monetary prize. The award was established by the 1895 will and estate of Swedish chemist and inventor Alfred Nobel. It was first awarded in Physics, Chemistry, Physiology or Medicine, Literature, and Peace in 1901...
-winning mathematician who was diagnosed with schizophrenia. The MarathiMarathi is an Indo-Aryan language spoken by the Marathi people of western and central India. It is the official language of the state of Maharashtra. There are 90 million fluent speakers worldwide. Marathi is the 4th most spoken language in India and the 15th most spoken language in the world...
film Devrai
(featuring Atul KulkarniAtul Kulkarni is an Indian actor who has won two National Awards.Atul Kulkarni is an Indian actor and winner of a National Award for his portrayal of Shriram Abhyankar in the film Hey Ram...
) is a presentation of a patient with schizophrenia. The film, set in Western IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
, shows the behavior, mentality, and struggle of the patient as well as his loved-ones. Other factual books have been written by relatives on family members; Australian journalist Anne DevesonAnne Barbara Deveson AO is an Australian writer, broadcaster, filmmaker and social commentator.During World War II, Deveson's family moved to Western Australia from Malaya as refugees. She attempted a Science degree in England, but dropped out to pursue other interests...
told the story of her son's battle with schizophrenia in Tell me I'm Here
, later made into a movie.
In Bulgakov'sMikhail Afanasyevich Bulgakov was a Russian contemporary novelist and playwright active in the first half of the 20th century...
The Master and MargaritaThe Master and Margarita is a novel by Mikhail Bulgakov, woven around the premise of a visit by the Devil to the fervently atheistic Soviet Union...
the poet Ivan Bezdomnyj is institutionalized and diagnosed with schizophrenia after witnessing the devil (Woland) predict Berlioz's death. The book The Eden ExpressThe Eden Express: A Memoir of Insanity is a 1975 book by Mark Vonnegut, son of American writer Kurt Vonnegut, about Mark's experiences in the late 1960s and his major psychotic breakdown and recovery...
by
Mark VonnegutMark Twain Vonnegut is an American pediatrician and memoirist. He is the son of the late writer Kurt Vonnegut, Jr. and his first wife, Jane Cox. He is also the brother of Edith and Nanette Vonnegut. He described himself in the preface to his 1975 book as "a hippie, son of a counterculture hero,...
recounts his struggle with schizophrenia and his recovering journey.
External links