Dissociative Identity Disorder (aka Multiple Personality Disorder)

Dissociative Identity Disorder (DID): definition, signs, symptoms of Dissociative Identity Disorder (DID), Multiple Personality Disorder (MPD).

Full description of Dissociative Identity Disorder (DID). Definition, signs, symptoms, causes of Dissociative Identity Disorder.

Description of Dissociative Identity Disorder

(Dissociative Identity Disorder was once referred to as Multiple Personality Disorder.)

Dissociative identity disorder is chronic and potentially disabling or fatal, although many with the disorder function very well and lead creative and productive lives. People with this disorder are prone to injuring themselves. They may engage in self-mutilation. Many attempt suicide.

In Dissociative Identity Disorder, some of a person's personalities are aware of important personal information, whereas other personalities are unaware. Some personalities appear to know and interact with one another in an elaborate inner world. For example, personality A may be aware of personality B and know what B does, as if observing B's behavior; personality B may or may not be aware of personality A. Other personalities may or may not be aware of personality B, and personality B may or may not be aware of them.

The switching of personalities and the lack of awareness of one's behavior in the other personalities often make life chaotic for people with dissociative identity disorder. Because the personalities often interact with each other, people with dissociative personality disorder report hearing inner conversations and the voices of other personalities commenting on their behavior or addressing them. They experience distortion of time, with time lapses and amnesia. They have feelings of detachment from one's self (depersonalization) and feelings that one's surroundings are unreal (derealization). They often have concern with issues of control, both self-control and the control of others. In addition, people with dissociative identity disorder tend to develop severe headaches or other bodily pain and may experience sexual dysfunction. Different clusters of symptoms occur at different times.

Diagnostic Criteria for Dissociative Identity Disorder (DID)

The presence of two or more distinct identities or personality states (each with its own relatively enduring pattern of perceiving, relating to, and thinking about the environment and self).

At least two of these identities or personality states recurrently take control of the person's behavior.

Inability to recall important personal information that is too extensive to be explained by ordinary forgetfulness.

The disturbance is not due to the direct physiological effects of a substance (e.g., blackouts or chaotic behavior during Alcohol Intoxication) or a general medical condition (e.g., complex partial seizures). Note: In children, the symptoms are not attributable to imaginary playmates or other fantasy play.

Causes of Dissociative Identity Disorder

According to the Merck Manual, Dissociative Identity Disorder appears to be caused by the interaction of several factors. These include overwhelming stress; an ability to separate one's memories, perceptions, or identity from conscious awareness; abnormal psychologic development, and insufficient protection and nurture during childhood. About 97 to 98% of adults with dissociative identity disorder report having been abused during childhood.

For comprehensive information on dissociative identity disorder (DID), visit the Dissociative Disorders Center in the Abuse Community.

Sources: 1. American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Washington, DC: American Psychiatric Association. 2. Merck Manual, Home Edition for Patients and Caregivers, last revised 2006.

APA Reference
Writer, H. (2009, January 2). Dissociative Identity Disorder (aka Multiple Personality Disorder), HealthyPlace. Retrieved on 2019, October 21 from

Last Updated: July 5, 2019

Medically reviewed by Harry Croft, MD

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