Dissociative Identity Disorder

Dissociative identity disorder (also known as multiple personality disorder) is a psychiatric diagnosis in which a person displays multiple distinct identities or personalities (known as alter egos or alters), each with its own pattern of perceiving and interacting with the environment. The diagnosis requires that at least two personalities routinely take control of the individual's behavior with an associated memory loss that goes beyond normal forgetfulness; in addition, symptoms cannot be the temporary effects of drug use or a general medical condition.