A
delusion is a false
beliefBelief is the psychological state in which an individual holds a proposition or premise to be true.-Belief, knowledge and epistemology:The terms belief and knowledge are used differently in philosophy....
held with absolute conviction despite superior evidence. Unlike
hallucinationA hallucination, in the broadest sense of the word, 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,...
s, delusions are always
pathologicalPsychopathology is the study of mental illness, mental distress, and abnormal/maladaptive behavior. The term is most commonly used within psychiatry where pathology refers to disease processes...
(the result of an
illnessIllness is a state of poor health. Illness is sometimes considered another word for disease. Others maintain that fine distinctions exist...
or illness process). As a pathology, it is distinct from a belief based on false or incomplete information,
dogmaDogma is the established belief or doctrine held by a religion, or a particular group or organization. It is authoritative and not to be disputed, doubted, or diverged from, by the practitioners or believers...
, poor
memoryIn psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
,
illusionAn illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people....
, or other effects of
perceptionPerception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
.
Delusions typically occur in the context of neurological or
mental illnessA mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...
, although they are not tied to any particular disease and have been found to occur in the context of many pathological states (both physical and mental). However, they are of particular diagnostic importance in
psychoticPsychosis 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"...
disorders including
schizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
,
paraphreniaParaphrenia is described as a group of psychotic illnesses distinct from paranoia and from schizophrenia.. Paraphrenia as a separate disorder is not included in either ICD 10 or DSM IV and is likely to be classified as atypical psychosis, schizoaffective disorder or delusional disorder using these...
,
manicMania, the presence of which is a criterion for certain psychiatric diagnoses, is a state of abnormally elevated or irritable mood, arousal, and/ or energy levels. In a sense, it is the opposite of depression...
episodes of
bipolar disorderBipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
, and
psychotic depressionPsychotic major depression is a type of depression that can include symptoms and treatments that are different from those of non-psychotic major depressive disorder . PMD is estimated to affect about 0.4% of the population .PMD is sometimes "mistaken" for NPMD, schizoaffective disorder,...
.
Definition
Although non-specific concepts of madness have been around for several thousand years, the psychiatrist and philosopher
Karl JaspersKarl Theodor Jaspers was a German psychiatrist and philosopher who had a strong influence on modern theology, psychiatry and philosophy. After being trained in and practicing psychiatry, Jaspers turned to philosophical inquiry and attempted to discover an innovative philosophical system...
was the first to define the three main criteria for a belief to be considered delusional in his 1913 book
General Psychopathology. These criteria are:
- certainty (held with absolute conviction)
- incorrigibility (not changeable by compelling counterargument or proof to the contrary)
- impossibility or falsity of content (implausible, bizarre or patently untrue)
Furthermore, when a false belief involves a value judgment, it is only considered as a delusion if it is so extreme that it cannot be or ever can be proven true (example: a man claims that he flew into the sun and flew back home. This would be considered a delusion).
Types
Delusions are categorized into four different groups:
- Bizarre delusion: A delusion that is very strange and completely implausible; an example of a bizarre delusion would be that aliens have removed the affected person's brain.
- Non-bizarre delusion: A delusion that, though false, is at least possible, e.g., the affected person mistakenly believes that he is under constant police surveillance.
- Mood-congruent delusion: Any delusion with content consistent with either a depressive or manic state, e.g., a depressed person believes that news anchors on television highly disapprove of him, or a person in a manic state might believe he is a powerful deity.
- Mood-neutral delusion: A delusion that does not relate to the sufferer's emotional state; for example, a belief that an extra limb is growing out of the back of one's head is neutral to either depression or mania.
Themes
In addition to these categories, delusions often manifest according to a consistent theme. Although delusions can have any theme, certain themes are more common. Some of the more common delusion themes are:
- Delusion of control: This is a false belief that another person, group of people, or external force controls one's general thoughts, feelings, impulses, or behavior.
- Nihilistic delusion: This is a false belief that one does not exist or has become deceased.
- Delusional jealousy (or delusion of infidelity)
Morbid jealousy is a psychiatric disorder in which a person holds a strong delusional belief that that their spouse or sexual partner is being unfaithful without having any, very little, or insignificant proof to back up their claim.-Definition:This disorder occurs when a person typically makes...
: A person with this delusion falsely believes that a person is lying to them or that a spouse or lover is having an affair, with no proof to back up their claim.
- Delusion of guilt or sin (or delusion of self-accusation): This is a false feeling of remorse or guilt of delusional intensity.
- Delusion of mind being read: The false belief that other people can know one's thoughts.
- Delusion of reference
Ideas of reference and delusions of reference involve people having a belief or perception that irrelevant, unrelated or innocuous phenomena in the world refer to them directly or have special personal significance: 'the notion that everything one perceives in the world relates to one's own...
: The person falsely believes that insignificant remarks, events, or objects in one's environment have personal meaning or significance.
- Erotomania
Erotomania is a type of delusion in which the affected person believes that another person, usually a stranger or famous person, is in love with him or her. The illness often occurs during psychosis, especially in patients with schizophrenia or bipolar mania...
A delusion where someone believes another person is in love with them.
- Religious delusion: Any delusion with a religious or spiritual content. These may be combined with other delusions, such as grandiose delusions (the belief that the affected person is a god, or chosen to act as a god, for example).
- Somatic delusion: A delusion whose content pertains to bodily functioning, bodily sensations, or physical appearance. Usually the false belief is that the body is somehow diseased, abnormal, or changed—for example, infested with parasites.
- Delusions of parasitosis (DOP) or delusional parasitosis
Delusional parasitosis is a form of psychosis whose victims acquire a strong delusional belief that they are infested with parasites, whereas in reality no such parasites are present...
: a delusion in which one feels infested with an insectInsects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
, bacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, miteMites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
, spiders, lice, fleas, wormThe term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s, or other organisms. Affected individuals may also report being repeatedly bitten. In some cases, entomologists are asked to investigate cases of mysterious bites. Sometimes physical manifestations may occur including skin lesions.
- Delusion of poverty: The person strongly believes that he is financially incapacitated. Although this type of delusion is less common now, it was particularly widespread in the days before state support.
Grandiose delusions
Grandiose delusions are distinct from
grandiosityGrandiosity is chiefly associated with narcissistic personality disorder, but also commonly features in manic or hypomanic episodes of bipolar disorder....
, in that the sufferer does not have insight into his loss of touch with reality. An individual is convinced he has special powers, talents, or abilities. Sometimes, the individual may actually believe they are a famous person or character (for example, Napoleon).
Grandiose delusions or delusions of grandeur are principally a subtype of
delusional disorderDelusional disorder is an uncommon psychiatric condition in which patients present with circumscribed symptoms of non-bizarre delusions, but with the absence of prominent hallucinations and no thought disorder, mood disorder, or significant flattening of affect...
but could possibly feature as a symptom of
schizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
and
manicMania, the presence of which is a criterion for certain psychiatric diagnoses, is a state of abnormally elevated or irritable mood, arousal, and/ or energy levels. In a sense, it is the opposite of depression...
episodes of bipolar disorder. Grandiose delusions are characterized by fantastical beliefs that one is famous, omnipotent, or otherwise very powerful. The delusions are generally fantastic, often with a
supernaturalThe supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...
, science-fictional, or religious bent. In colloquial usage, one who overestimates one's own abilities, talents, stature or situation is sometimes said to have 'delusions of grandeur'. This is generally due to excessive
pridePride is an inwardly directed emotion that carries two common meanings. With a negative connotation, pride refers to an inflated sense of one's personal status or accomplishments, often used synonymously with hubris...
, rather than any actual
delusionA delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
s.
Persecutory delusions
Persecutory delusions are the most common type of delusions and involve the theme of being followed, harassed, cheated, poisoned or drugged, conspired against, spied on, attacked, or obstructed in the pursuit of goals.
Persecutory delusions are a condition in which the affected person believes - wrongly – they are being
persecutedPersecution is the systematic mistreatment of an individual or group by another group. The most common forms are religious persecution, ethnic persecution, and political persecution, though there is naturally some overlap between these terms. The inflicting of suffering, harassment, isolation,...
. Specifically, they have been defined as containing two central elements:
- The individual thinks that harm is occurring, or is going to occur.
- The individual thinks that the persecutor has the intention to cause harm.
According to the DSM-IV-TR, persecutory delusions are the most common form of delusions in
schizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
, where the person believes they are "being tormented, followed, tricked, spied on, or ridiculed." In the DSM-IV-TR, persecutory delusions are the main feature of the persecutory type of
delusional disorderDelusional disorder is an uncommon psychiatric condition in which patients present with circumscribed symptoms of non-bizarre delusions, but with the absence of prominent hallucinations and no thought disorder, mood disorder, or significant flattening of affect...
. When the focus is to remedy some injustice by legal action, they are sometimes called "querulous paranoia".
Diagnosis
The modern definition and Jaspers' original criteria have been criticised, as counter-examples can be shown for every defining feature.
Studies on psychiatric patients show that delusions vary in intensity and conviction over time, which suggests that certainty and incorrigibility are not necessary components of a delusional belief.
Delusions do not necessarily have to be false or 'incorrect inferences about external reality'. Some religious or spiritual beliefs by their nature may not be falsifiable, and hence cannot be described as false or incorrect, no matter whether the person holding these beliefs was diagnosed as delusional or not.
In other situations the delusion may turn out to be true belief. For example,
delusional jealousyMorbid jealousy is a psychiatric disorder in which a person holds a strong delusional belief that that their spouse or sexual partner is being unfaithful without having any, very little, or insignificant proof to back up their claim.-Definition:This disorder occurs when a person typically makes...
, where a person believes that their partner is being unfaithful (and may even follow them into the bathroom believing them to be seeing their lover even during the briefest of partings) may result in the faithful partner being driven to infidelity by the constant and unreasonable strain put on them by their delusional spouse. In this case the delusion does not cease to be a delusion because the content later turns out to be true.
In other cases, the delusion may be assumed to be false by a doctor or psychiatrist assessing the belief, because it
seems to be unlikely, bizarre or held with excessive conviction. Psychiatrists rarely have the time or resources to check the validity of a person’s claims leading to some true beliefs to be erroneously classified as delusional. This is known as the
Martha Mitchell effectThe Martha Mitchell effect is the process by which a psychiatrist, psychologist, or other mental health clinician mistakes the patient's perception of real events as delusional and misdiagnoses accordingly.-Description:...
, after the wife of the
attorney generalThe United States Attorney General is the head of the United States Department of Justice concerned with legal affairs and is the chief law enforcement officer of the United States government. The attorney general is considered to be the chief lawyer of the U.S. government...
who alleged that illegal activity was taking place in the
White HouseThe White House is the official residence and principal workplace of the president of the United States. Located at 1600 Pennsylvania Avenue NW in Washington, D.C., the house was designed by Irish-born James Hoban, and built between 1792 and 1800 of white-painted Aquia sandstone in the Neoclassical...
. At the time her claims were thought to be signs of mental illness, and only after the
Watergate scandalThe Watergate scandal was a political scandal during the 1970s in the United States resulting from the break-in of the Democratic National Committee headquarters at the Watergate office complex in Washington, D.C., and the Nixon administration's attempted cover-up of its involvement...
broke was she proved right (and hence sane).
Similar factors have led to criticisms of Jaspers' definition of true delusions as being ultimately 'un-understandable'. Critics (such as R. D. Laing) have argued that this leads to the diagnosis of delusions being based on the
subjectiveSubjectivity refers to the subject and his or her perspective, feelings, beliefs, and desires. In philosophy, the term is usually contrasted with objectivity.-Qualia:...
understanding of a particular psychiatrist, who may not have access to all the information that might make a belief otherwise interpretable. R.D. Laing's hypothesis has been applied to some forms of projective therapy to "fix" a delusional system so that it cannot be altered by the patient. Psychiatric researchers at
Yale UniversityYale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...
,
Ohio State UniversityThe Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...
and the Community Mental Health Center of Middle Georgia have used novels and motion picture films as the focus. Texts, plots and cinematography are discussed and the delusions approached tangentially. This use of fiction to decrease the malleability of a delusion was employed in a joint project by science-fiction author
Philip Jose FarmerPhilip José Farmer was an American author, principally known for his award-winning science fiction and fantasy novels and short stories....
and Yale psychiatrist A. James Giannini. They wrote the novel
Red Orc's RageRed Orc's Rage is a recursive science fiction novel and part of the "World of Tiers" series of novels by Philip José Farmer. The plot of the book was inspired by the work of American psychiatrist A.James Giannini, M.D, who used earlier books in Farmer's series as role-playing tools and aids to...
, which, recursively, deals with delusional adolescents who are treated with a form of projective therapy. In this novel's fictional setting other novels written by Farmer are discussed and the characters are symbolically integrated into the delusions of fictional patients.This particular novel was then applied to real-life clinical settings.
Another difficulty with the diagnosis of delusions is that almost all of these features can be found in "normal" beliefs. Many religious beliefs hold exactly the same features, yet are not universally considered delusional. These factors have led the psychiatrist
Anthony 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...
to note that "there is no acceptable (rather than accepted) definition of a delusion." In practice psychiatrists tend to diagnose a belief as delusional if it is either patently bizarre, causing significant distress, or excessively pre-occupies the patient, especially if the person is subsequently unswayed in belief by counter-evidence or reasonable arguments.
It is important to distinguish true delusions from other symptoms such as
anxietyAnxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
,
fearFear is a distressing negative sensation induced by a perceived threat. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of danger...
, or
paranoiaParanoia [] is a thought process believed to be heavily influenced by anxiety or fear, often to the point of irrationality and delusion. Paranoid thinking typically includes persecutory beliefs, or beliefs of conspiracy concerning a perceived threat towards oneself...
. To diagnose delusions a mental state examination may be used. This test includes
appearanceHuman physical appearance refers to the outward phenotype or look of human beings. There are infinite variations in human phenotypes, though society reduces the variability to distinct categories...
,
moodA mood is a relatively long lasting emotional state. Moods differ from emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event....
, affect,
behaviorBehavior or behaviour refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with its environment, which includes the other systems or organisms around as well as the physical environment...
, rate and continuity of speech,evidence of hallucinations or abnormal beliefs, thought content, orientation to time, place and person, attention and
concentrationIn chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...
, insight and judgment, as well as short-term
memoryIn psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
.
Johnson-Laird suggests that delusions may be viewed as the natural consequence of failure to distinguish conceptual relevance. That is, the person takes irrelevant information and puts it in the form of disconnected experiences, then it is taken to be relevant in a manner that suggests false causal connections. Furthermore, the person takes the relevant information, in the form of counterexamples, and ignores it.
Development of specific delusions
The top two factors mainly concerned in the germination of delusions are: 1. Disorder of brain functioning; and 2. background influences of temperament and personality.
Higher levels of dopamine qualify as a symptom of disorders of brain function. That they are needed to sustain certain delusions was examined by a preliminary study on delusional disorder (a psychotic syndrome) instigated to clarify if schizophrenia had a dopamine psychosis. There were positive results - delusions of jealousy and persecution had different levels of dopamine metabolite
HVAHomovanillic acid is a major catecholamine metabolite...
and
Homovanillyl alcoholHomovanillyl alcohol is a metabolite of hydroxytyrosol, which in turn is a metabolite of the neurotransmitter dopamine....
(which may have been genetic). These can be only regarded as tentative results; the study called for future research with a larger population.
It is too simplistic to say that a certain measure of dopamine will bring about a specific delusion. Studies show age and gender to be influential and it is most likely that HVA levels change during the life course of some syndromes.
On the influence personality, it has been said: "Jaspers considered there is a subtle change in personality due to the illness itself; and this creates the condition for the development of the delusional atmosphere in which the delusional intuition arises."
Cultural factors have "a decisive influence in shaping delusions". For example, delusions of guilt and punishment are frequent in a Western, Christian country like Austria, but not in Pakistan - where it is more likely persecution. Similarly, in a series of case studies, delusions of guilt and punishment were found in Austrian patients with Parkinson's being treated with l-dopa - a dopamine agonist.
Causes
To define delusional thinking in a specific patient, it is important to consult a local psychiatrist who can make a thorough examination before diagnosing the problem. Explaining the causes of delusions has been challenging and several theories have been developed. One is the
geneticGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
or biological theory, which states that close relatives of people with delusional disorder are at increased risk of delusional traits. Another theory is the dysfunctional cognitive processing, which states that delusions may arise from distorted ways people have of explaining life to themselves. A third theory is called motivated or defensive delusions. This one states that some of those persons who are predisposed might suffer the onset of delusional disorder in those moments when coping with life and maintaining high
self-esteemSelf-esteem is a term in psychology to reflect a person's overall evaluation or appraisal of his or her own worth. Self-esteem encompasses beliefs and emotions such as triumph, despair, pride and shame: some would distinguish how 'the self-concept is what we think about the self; self-esteem, the...
becomes a significant challenge. In this case, the person views others as the cause of their personal difficulties in order to preserve a positive self-view.
This condition is more common among people who have poor
hearingHearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
or
sightVisual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
. Also, ongoing stressors have been associated with a higher possibility of developing delusions. Examples of such stressors are
immigrationImmigration is the act of foreigners passing or coming into a country for the purpose of permanent residence...
or low socio-economic status.
Researcher, Orrin Devinsky, MD, from the NYU Langone Medical Center, performed a study that revealed a consistent
patternA pattern, from the French patron, is a type of theme of recurring events or objects, sometimes referred to as elements of a set of objects.These elements repeat in a predictable manner...
of injury to the
frontal lobeThe frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
and right hemisphere of the
human brainThe human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
in patients with certain delusions and brain disorders. Devinsky explains that the cognitive deficits caused by those injuries to the right hemisphere, results in the over compensation by the left hemisphere of the brain for the injury, which causes delusions.
A study carried out by a team from The Warwick Medical School at the
University of WarwickThe University of Warwick is a public research university located in Coventry, United Kingdom...
, Coventry, England, led by Andrea Schreier, Ph. D., indicated that children who suffered bullying are more likely to develop psychotic symptoms in early
adolescenceAdolescence is a transitional stage of physical and mental human development generally occurring between puberty and legal adulthood , but largely characterized as beginning and ending with the teenage stage...
. The background facts demonstrated that hallucinations and delusions are common in childhood as well as in adulthood and that children who experience such symptoms are more prone to develop psychosis later in life. Furthermore, the study demonstrated that the risk of psychotic symptoms, including delusions, was multiplied by two for children who suffered bullying at age eight or ten. The authors remark that bullying can cause
chronic stressChronic stress is the response to emotional pressure suffered for a prolonged period over which an individual perceives he or she has no control. It involves an endocrine system response in which occurs a release of corticosteroids...
that may have an effect on a genetic predisposition to schizophrenia and result in setting off the symptoms.
Further reading