Conversion disorder

Conversion disorder is a neurosis marked by the appearance of physical symptoms such as partial loss of muscle function without physical cause but in the presence of psychological conflict. Symptoms include numbness, blindness, paralysis, or fits 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 fourth edition (DSM-IV).

Formerly known as "hysteria", 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 and Sigmund Freud and psychiatrist Pierre Janet 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 while the ICD-10 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 or malingering).

• 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, does not occur exclusively during the course of somatization disorder, and is not better accounted for by another mental disorder.

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 International Classification of Diseases uses the term "conversion" as an alternative descriptor for the dissociative disorders class of mental and behavioural disorders (i.e. the F44 class), with the explicit suggestion that dissociative 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 in the US and Paul Briquet and Jean-Martin Charcot 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.", 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)
• Psychogenic non-epileptic seizures
• Fixed dystonia unlike normal dystonia^{[clarification needed]}
• Tremor, myoclonus or other movement disorders
• Gait problems (Astasia-abasia)
• Syncope (fainting)
• Hallucinations of a childish or fantastical nature
• Tourette-like symptoms

Mass psychogenic illness

The DSM-IV-TR does not have specific diagnosis for mass psychogenic illness 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."