Dissociative identity disorder (DID)

Formerly known as multiple personality disorder. It consists of the existence within one person of two or more distinct personalities or personality states (alters or alter personalities). Each personality state has its own relatively enduring pattern of perceiving, relating to, and thinking about the environment and the self, and at least two of them alternate in taking control of the person’s behavior. Characteristically, there is an amnesic barrier between personalities, which may be absolute or, more commonly, unilateral, denying one personality access to the memories of the other but allowing the other personality full access to the memory systems of both.

Dissociative identity disorder (DID), formerly known as multiple personality disorder (MPD), occurs when a child experiences more than one identity or personality state controlling the child’s behavior at different times. The child may or may not be aware that he or she possesses different identities (or “alters”), and switching between alters may occur within seconds. As a result, the child often suffers lapses of memory, which represent failure to recall information that was presented, or events that occurred, when the child was in a different identity or personality state. Children with DID may experience periods of time for which they cannot account for, find items in their possession without knowing how or when they acquired them, meet people who know them but whom they do not recognize, and fail to remember material that they have learned in class. Although many individuals with DID can function well for a time, most will experience periods of decompensation marked by severe anxiety, depression, hallucinations, flashbacks, or other psychiatric symptoms.

A rare but increasingly reported psychiatric illness in which a person has two (or more) distinct personalities. It was formerly known as “multiple personality disorder.” The patient’s personalities may vary broadly with respect to interests, communication styles, aggression, and gender. Amnesia for differing personalities is characteristic.