Conversion disorder
Encyclopedia
Conversion disorder is a condition in which patients present with neurological symptoms such as numbness, blindness
Blindness
Blindness 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...

, paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...

, or fits
Psychogenic non-epileptic seizures
Psychogenic non-epileptic seizures , also known as Non-Epileptic Attack Disorders, are events superficially resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy. Instead, PNES are psychological in origin, and may be thought of as similar to...

 without a neurological cause. It is thought that these problems arise in response to difficulties in the patient's life, and conversion is considered a psychiatric disorder in the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV). Formerly known as "hysteria
Female hysteria
Female hysteria was a once-common medical diagnosis, made exclusively in women, which is today no longer recognized by modern medical authorities as a medical disorder. Its diagnosis and treatment were routine for many hundreds of years in Western Europe. Hysteria was widely discussed in the...

", the disorder has arguably been known for millennia, though it came to greatest prominence at the end of the 19th century, when the neurologists Jean-Martin Charcot
Jean-Martin Charcot
Jean-Martin Charcot was a French neurologist and professor of anatomical pathology. He is known as "the founder of modern neurology" and is "associated with at least 15 medical eponyms", including Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis...

 and Sigmund Freud
Sigmund Freud
Sigmund Freud , born Sigismund Schlomo Freud , was an Austrian neurologist who founded the discipline of psychoanalysis...

 and psychiatrist Pierre Janet
Pierre Janet
Pierre Marie Félix Janet was a pioneering French psychologist, philosopher and psychotherapist in the field of dissociation and traumatic memory....

 focused their studies on the subject. The term "conversion" has its origins in Freud's doctrine that anxiety is "converted" into physical symptoms. Though previously thought to have vanished from the west in the 20th century, some research has suggested it is as common as ever.

The DSM-IV classifies conversion disorder as a somatoform disorder
Somatoform disorder
In psychology, a somatoform disorder is a mental disorder characterized by physical symptoms that suggest physical illness or injury - symptoms that cannot be explained fully by a general medical condition, direct effect of a substance, or attributable to another mental disorder . The symptoms that...

 while the ICD-10
ICD-10
The International Statistical Classification of Diseases and Related Health Problems, 10th Revision is a medical classification list for the coding of diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases, as maintained by the...

 classifies it as a dissociative disorder.

Definition

DSM-IV defines conversion disorder as follows:
  • One or more symptoms or deficits are present that affect voluntary motor or sensory function suggestive of a neurologic or other general medical condition.

  • Psychological factors are judged, in the clinician's belief, to be associated with the symptom or deficit because conflicts or other stressors precede the initiation or exacerbation of the symptom or deficit. A diagnosis where the stressor precedes the onset of symptoms by up to 15 years is not unusual.

  • The symptom or deficit is not intentionally produced or feigned (as in factitious disorder
    Factitious disorder
    Factitious disorders are conditions in which a person acts as if he or she has an illness by deliberately producing, feigning, or exaggerating symptoms. Factitious disorder by proxy is a condition in which a person deliberately produces, feigns, or exaggerates symptoms in a person who is in their...

     or malingering
    Malingering
    Malingering is a medical term that refers to fabricating or exaggerating the symptoms of mental or physical disorders for a variety of "secondary gain" motives, which may include financial compensation ; avoiding school, work or military service; obtaining drugs; getting lighter criminal sentences;...

    ).

  • The symptom or deficit, after appropriate investigation, cannot be explained fully by a general medical condition, the direct effects of a substance, or as a culturally sanctioned behavior or experience.

  • The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.

  • The symptom or deficit is not limited to pain or sexual dysfunction
    Sexual dysfunction
    Sexual dysfunction or sexual malfunction refers to a difficulty experienced by an individual or a couple during any stage of a normal sexual activity, including desire, arousal or orgasm....

    , does not occur exclusively during the course of somatization disorder
    Somatization disorder
    Somatization disorder is a psychiatric diagnosis applied to patients who persistently complain of varied physical symptoms that have no identifiable physical origin...

    , and is not better accounted for by another mental disorder
    Mental illness
    A 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,...

    .


The nature of the association between the psychological factors and the neurological symptoms remains unclear. Earlier versions of the DSM-IV employed psychodynamic concepts, but these have been incrementally removed from successive versions.

The tenth revision of the World Health Organization's
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

 International Classification of Diseases
ICD-10
The International Statistical Classification of Diseases and Related Health Problems, 10th Revision is a medical classification list for the coding of diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases, as maintained by the...

 uses the term "conversion" as an alternative descriptor for the dissociative disorders
Dissociative disorders
Dissociative disorders are defined as conditions that involve disruptions or breakdowns of memory, awareness, identity and/or perception. See also dissociation. People with dissociative disorders are able to escape from reality involuntarily...

 class of mental and behavioural disorders (i.e. the F44 class), with the explicit suggestion that dissociative
Dissociation
Dissociation is an altered state of consciousness characterized by partial or complete disruption of the normal integration of a person’s normal conscious or psychological functioning. Dissociation is most commonly experienced as a subjective perception of one's consciousness being detached from...

 and conversion symptoms probably share common psychological mechanisms. In ICD-10, the dissociative [conversion] disorders class includes 10 disorders that, in addition to specific criteria for each individual disorder, must each meet the following general criteria:
  • No evidence of a physical disorder that can explain the symptoms that characterize the disorder (but physical disorders may be present that give rise to other symptoms);
  • Convincing associations in time between the symptoms of the disorder and stressful events, problems or needs.

History

In the 19th century, physicians such as Silas Weir Mitchell
Silas Weir Mitchell
Silas Weir Mitchell was an American physician and writer.He was son of a physician, John Kearsley Mitchell , and was born in Philadelphia, Pennsylvania....

 in the US and Paul Briquet and Jean-Martin Charcot
Jean-Martin Charcot
Jean-Martin Charcot was a French neurologist and professor of anatomical pathology. He is known as "the founder of modern neurology" and is "associated with at least 15 medical eponyms", including Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis...

 in France developed ideas about patients sharing unexplained neurological symptoms. Charcot specialised in treating patients who were suffering from a variety of unexplained physical symptoms including paralysis, contractures (muscles which contract and cannot be relaxed) and seizures. Some of these patients sporadically and compulsively adopted a bizarre posture (christened arc-de-cercle) in which they arched their body backwards until they were supported only by their head and their heels.

The term "Conversion disorder" originated with Freud. He viewed these apparently neurological symptoms as a result of the conversion of intrapsychic distress into physical symptoms. This distress was thought to cause the brain to unconsciously disable or impair a bodily function as a side effect of the original repression, which served to relieve the patient's anxiety. However, recent evidence suggests that patients do remain distressed by their symptoms in the long term It has also been suggested that at least some of the classic psychoanalytic cases of hysteria, such as "Anna O.
Anna O.
Anna O. was the pseudonym of a patient of Josef Breuer, who published her case study in his book Studies on Hysteria, written in collaboration with Sigmund Freud. Her real name was Bertha Pappenheim , an Austrian-Jewish feminist and the founder of the Jüdischer Frauenbund .Anna O...

", may actually have suffered from organic illness.
In fact, in Studies On Hysteria in which Breuer's Anna O. case was first presented, Freud wrote this: "Others of the patient's symptoms were not of a hysterical nature at all. This is true, for example, of the neck cramps, which I consider a modified version of migraine and which as such are not to be classified as a neurosis but as an organic disorder. Hysterical symptoms, however, regularly become attached to these." Freud believed that all hysterical symptoms ultimately have some organic components.

Presentation

Conversion disorder can present with any motor or sensory symptom including any of the following:
  • Weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)
  • Impaired vision (hysterical blindness) or impaired hearing
  • Loss/disturbance of sensation
  • Impairment or loss of speech (hysterical aphonia
    Aphonia
    Aphonia is the inability to speak. It is considered more severe than dysphonia. A primary cause of aphonia is bilateral disruption of the recurrent laryngeal nerve, which supplies nearly all the muscles in the larynx...

    )
  • Psychogenic non-epileptic seizures
    Psychogenic non-epileptic seizures
    Psychogenic non-epileptic seizures , also known as Non-Epileptic Attack Disorders, are events superficially resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy. Instead, PNES are psychological in origin, and may be thought of as similar to...

  • Fixed dystonia
    Dystonia
    Dystonia is a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning or reaction to...

     unlike normal dystonia
  • Tremor, myoclonus or other movement disorders
  • Gait problems (Astasia-abasia)
  • Syncope (fainting)
  • Hallucinations of a childish or fantastical nature

Mass Psychogenic Illness

The DSM-IV-TR does not have specific diagnosis for Mass Psychogenic Illness
Mass Psychogenic Illness
Mass psychogenic illness , also called mass sociogenic illness, is “the rapid spread of illness signs and symptoms affecting members of a cohesive group, originating from a nervous system disturbance involving excitation, loss or alteration of function, whereby physical complaints that are...

 but the text describing conversion disorder states that "In 'epidemic hysteria,' shared symptoms develop in a circumscribed group of people following 'exposure' to a common precipitant."

Diagnosis

The diagnosis of conversion disorder involves three elements: the exclusion of neurological disease, the exclusion of feigning, and the determination of a psychological mechanism. Each of these has difficulties.

Exclusion of neurological disease

Conversion disorder presents with symptoms that typically resemble a neurological disorder such as stroke, multiple sclerosis, epilepsy or hypokalemic periodic paralysis
Hypokalemic periodic paralysis
Hypokalemic periodic paralysis is a rare channelopathy characterized by muscle weakness or paralysis with a matching fall in potassium levels in the blood...

. The neurologist must carefully exclude neurological disease, through examination and appropriate investigations. However, it is not uncommon for patients with neurological disease to also have conversion disorder, in which case the task becomes to determine how much of the patient's problem is due to conversion.

In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder — certain aspects of the presentation that were thought to be rare in neurological disease, but common in conversion. The validity of many of these signs has been questioned, however, by a study showing that they also occurred in neurological disease. One such symptom, for example, is La belle indifférence, described in DSM-IV as "a relative lack of concern about the nature or implications of the symptoms". In a later study no evidence was found that patients with "functional" symptoms are any more likely to exhibit this than patients with a confirmed organic disease. Another feature thought to be important was that symptoms would tend to be more severe on the non-dominant (usually left) side; there were a variety of theories such as the relative involvement of cerebral hemispheres in emotional processing, or more simply just that it was "easier" to live with a functional deficit on the non-dominant side. However, a literature review of 121 studies established that this was not true, with publication bias
Publication bias
Publication bias is the tendency of researchers, editors, and pharmaceutical companies to handle the reporting of experimental results that are positive differently from results that are negative or inconclusive, leading to bias in the overall published literature...

 the most likely explanation for this commonly held view. Although agitation is often assumed to be a positive sign of conversion disorder, release of epinephrine is a well-demonstrated cause of paralysis from hypokalemic periodic paralysis
Hypokalemic periodic paralysis
Hypokalemic periodic paralysis is a rare channelopathy characterized by muscle weakness or paralysis with a matching fall in potassium levels in the blood...

.

The process of exclusion is not perfect, so misdiagnoses will occur. However, in a highly influential study from the 1960s, Eliot Slater demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder. Later authors have argued that the paper was flawed, however, and a meta-analysis has shown that misdiagnosis rates since that paper are around 4%, the same as for other neurological diseases.

Exclusion of feigning

Conversion disorder is unique in DSM-IV in explicitly requiring the exclusion of deliberate feigning. Unfortunately, this is only likely to be demonstrable where the patient confesses, or is "caught out" in a broader deception, such as a false identity. One neuroimaging study suggested that feigning may be distinguished from conversion by the pattern of frontal lobe activation; however this is a research, rather than a clinical technique. True rates of feigning in medicine remain unknown, though neurological presentations of feigning may be among the more common.

Establishing a psychological mechanism

The psychological mechanism can be the most difficult aspect of the conversion diagnosis. DSM-IV requires that the clinician believe preceding stressors or conflicts to be associated with the development of the disorder, though how this might come about is still the subject of debate.

Causes

The original Freudian model suggested that the emotional charge of painful experiences would be consciously repressed as a way of managing the pain, but this emotional charge would be somehow "converted" into the neurological symptoms. Freud later argued that the repressed experiences were of a sexual nature. As Peter Halligan comments, conversion has 'the doubtful distinction among psychiatric diagnoses of still invoking Freudian mechanisms' Janet, the other great theoretician of hysteria, argued that symptoms arose through the power of suggestion, acting on a personality vulnerable to dissociation
Dissociation
Dissociation is an altered state of consciousness characterized by partial or complete disruption of the normal integration of a person’s normal conscious or psychological functioning. Dissociation is most commonly experienced as a subjective perception of one's consciousness being detached from...

. In this hypothetical process, the subject's experience of their leg, for example, is split-off from the rest of their consciousness, resulting in paralysis or numbness in that leg. Later authors have attempted to combine elements of these models, but none of them has a firm empirical basis. Some support for the Freudian model comes from findings of high rates of childhood sexual abuse in conversion patients and from a recent neuroimaging study showing abnormal emotion processing of a traumatic event linked to motor processing of the affected limb, in a patient with conversion. Support for the dissociation model comes from studies showing heightened suggestibility in conversion patients, and in abnormalities in motor imagery.
There has been much recent interest in functional neuroimaging in conversion. As researchers identify the mechanisms which underlie conversion symptoms it is hoped these will allow the development of a neuropsychological model. A number of such studies have been performed, including some which suggest that blood flow in patients brains may be abnormal while they are unwell. These have all been too small to be confident of the generalisability of their findings, however, so no neuropsychological model has been clearly established.

A 2007 review stated that conversion disorder and dissociative disorders are statically associated, share features such as a history of abuse and high suggestability, and likely have common underlying causes. It recommended that DSM should follow ICD-10 and reclassify conversion disorder from a somatoform disorder to a dissociative disorder.

An evolutionary psychology
Evolutionary psychology
Evolutionary psychology is an approach in the social and natural sciences that examines psychological traits such as memory, perception, and language from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations, that is, the functional...

 explanation for conversion disorder is that the symptom may have been evolutionarily advantageous during warfare. A non-combatant with these symptoms signals non-verbally, possibly to someone speaking a different language, that she or he is not dangerous as a combatant and also may be carrying some form of dangerous infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...

. This can explain that conversion disorder may develop following a threatening situation, that there may be a group effect with many people simultaneously developing similar symptoms (as in Mass Psychogenic Illness
Mass Psychogenic Illness
Mass psychogenic illness , also called mass sociogenic illness, is “the rapid spread of illness signs and symptoms affecting members of a cohesive group, originating from a nervous system disturbance involving excitation, loss or alteration of function, whereby physical complaints that are...

), and the gender difference in prevalence.

Prevalence

Information on the prevalence of conversion disorder in the West is limited, in part due to the complexities of the diagnostic process. In neurological settings, rates of unexplained symptoms are very high, at between 30 and 60%, which suggests conversion to be more common than most neurological diseases. However, the diagnosis of conversion typically requires an additional psychiatric evaluation, yet few patients will see a psychiatrist so an unknown fraction of those unexplained symptoms will be due to conversion. Large scale psychiatric registers in the US and Iceland found rates of 22 and 11 per 100000 per year, respectively, but it is unclear what proportion of unexplained symptoms these represent.

Culture

It is often thought that rates are higher outside of the West, perhaps related to cultural and medical attitudes, though evidence for this is again limited. A community survey of urban Turkey found a rate of 5.6%. Many authors have found rates to be higher in rural and lower socio-economic groups where technological investigation of patients is limited.

Gender

'Hysteria' was originally understood to be a condition exclusively affecting women, though it has increasingly been recognised in men. In recent, larger studies, women continue to predominate, with between 2 and 6 female patients for every male.

Age

Conversion disorder may present at any age but is rare in children younger than 10 years or in the elderly. Studies suggest a peak onset in the mid-to-late 30s.

Treatment

Treatment may include the following:
  1. Explanation. This must be clear and coherent as attributing physical symptoms to a psychological cause is not accepted by many educated people in western cultures. It must emphasise the genuineness of the condition, that it is common, potentially reversible and does not mean that the sufferer is a "psycho". Taking an aetiologically neutral stance by describing the symptoms as functional may be helpful but further studies are required. Ideally, the patient should be followed up neurologically for a while to ensure that the diagnosis has been understood.
  2. Physiotherapy where appropriate;
  3. Occupational Therapy to maintain autonomy in activities of daily living;
  4. Treatment of comorbid depression or anxiety if present.


There is little evidence-based treatment of conversion disorder. Other treatments such as cognitive behavioral therapy, hypnosis
Hypnosis
Hypnosis is "a trance state characterized by extreme suggestibility, relaxation and heightened imagination."It is a mental state or imaginative role-enactment . It is usually induced by a procedure known as a hypnotic induction, which is commonly composed of a long series of preliminary...

, EMDR, and psychodynamic psychotherapy
Psychodynamic psychotherapy
Psychodynamic psychotherapy is a form of depth psychology, the primary focus of which is to reveal the unconscious content of a client's psyche in an effort to alleviate psychic tension. In this way, it is similar to psychoanalysis. It also relies on the interpersonal relationship between client...

need further trials.

Prognosis

The DSM-IV-TR states that conversion symptoms will in most cases disappear within 2 weeks in those hospitalized. One-fifth to one-quarter will have a recurrence within a year with this also predicting future recurrences. Acute onset, clearly identifiable stress at this time, and short time between onset and treatment are associated with a favorable prognosis.
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