A conversion disorder is a relatively uncommon mental disorder in which a person has physical symptoms that no medical condition, physical examination or testing can explain. The person is not "faking." The symptoms do not appear to be under the person's conscious control and they can cause significant distress. Examples of symptoms are a loss of muscle control, blindness, deafness, seizures or even apparent unconsciousness.
The term "conversion" comes from the idea that psychological distress is being converted into a physical symptom. The cause is not known.
A long-standing theory has been that a person with conversion disorder must block out the source of the distress — be it a conflict or stress — because it is too unacceptable for the person to remain aware of it. There is, however, little formal evidence to support this theory.
The symptoms of this disorder often involve muscle control. But there is usually no abnormality in the motor systems in the brain or other nerves throughout the body. Nonetheless, patients appear to experience a loss of motor control. Research suggests that some of these individuals have abnormalities in parts of the brain that register and regulate emotion and interact with the core motor network.
Conversion disorder is more common in women than in men. It occurs most frequently between adolescence and middle age. Although relatively rare in the general population, conversion symptoms may be found in up to 14% of patients in general hospitals. In some reviews, they accounted for about 30% of symptoms among neurology outpatients.
A significant percentage of people with conversion disorder have another psychiatric problem, such as generalized anxiety, obsessive-compulsive disorder or some form of depression. There may have been a recent stress or trauma. People with the disorder also report a higher than average frequency of emotional or physical abuse during childhood.