Dissociative disorders are psychological phenomena in which there is a breakdown in an individual’s memory, awareness, identity, or perception. Such disorders are thought to result from the experience of extremely stressful, traumatic events or situations that a person psychologically escapes (dissociates) from as a defense mechanism. Depersonalization disorder is a type of dissociative disorder in which an individual feels detached from his or her normal perceptions of reality—as if the person is in a dream state. Persons affected by this disorder may experience feelings of being outside their body, may feel that the everyday environment is unfamiliar, or feel that they are losing control of their movements or actions. Dissociative identity disorder or multiple personality disorder is a famous type of dissociative disorder in which a person evidences one or more identities that surface on a recurring basis. Due to its bizarre nature, both professionals and laymen have frequently questioned the validity of this disorder. It has been dramatized in books and movies such as The There Faces of Eve and Sybil. Dissociative identity disorder is usually associated with severe physical or emotional childhood abuse. A very rare form of dissociation, dissociative fugue, involves persons unexpectedly leaving and turning up in a different place, confused or oblivious as to how they got there and who they are. Such dissociation can be brief or can last for several months. Persons suffering from this disorder may even assume a new identity. Dissociative amnesia occurs when someone blocks out personal information, usually related to traumatic or stressful events. Such amnesia is purely psychological, as opposed to someone forgetting information after a blow to the head. Dissociative amnesia varies as to what or how much information is forgotten, and how long the information is forgotten.

Somatoform disorders are psychosomatic in nature—they present physical symptoms with no apparent medical cause. Conversion disorder is one type of somatoform disorder in which the individual experiences blindness, paralysis, or convulsions in the absence of any discernible medical causes. Another type of this condition is pain disorder, where the sufferer experiences chronic pain for months or even years. Again, there is no apparent medical basis for the symptoms. Like dissociative disorders, somatoform disorders are attributed to an involuntary reaction to stressful or traumatic experiences. In this type of disorder, stress and trauma that is too painful to be processed psychologically is manifested physically—the individual copes with the physical distress rather than the psychological pain.