Conversion Disorder

Conversion disorder causes patients to suffer apparently neurological symptoms, such as numbness, blindness, paralysis, or fits, but 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. Before Freud's studies on hysteria, people who suffered from physical disabilities that were not caused by any physical impairments, known as hysterical patients, were believed to be malingering, suffering from weak nerves, or just suffering from meaningless disturbances. 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.