This is the 2007 version. Click here for the 2017 chapter 12 table of contents.

Dissociative Identity Disorder

The most dramatic and unusual dissociative state is multiple personality disorder (MPD), which was, renamed dissociative identity disorder (DID) in the 4th edition of the DSM manual. DID occurs when there are two or more executives or selves that take turns controlling a person's mental apparatus. As noted in the discussion of multiple personality in Chapter 11, DID can be described as a "post-traumatic stress syndrome of childhood origin." In the best-documented cases, the disorder was triggered by emotional trauma early in life.

What is "multiple personality disorder" called in DSM-IV?

Dissociative amnesia

Another dissociative disorder described in DSM-IV is dissociative amnesia : the temporary forgetting of personal information. Usually it is set off by a trauma. For example, a young man accidentally ran over a young girl. He thought for a moment that he had killed her, although it turned out she was barely injured. He drove away after finding out she was OK, but a few hours later he was found wandering aimlessly. He did not know his own name. When relatives came to the Emergency Room and talked to him, his memory gradually returned.

What is dissociative amnesia?

This case is typical of dissociative amnesia in several respects. The memory loss was triggered by a stressful incident, and it was reversible. Dissociative amnesia is interesting to psychologists who study memory, because it appears to show a separation between memory systems for personal information (which are affected by dissociative amnesia) and memory for facts and procedures (which are not affected). For example, a person with dissociative amnesia may not know his or her own name, but the person is likely to know who won the last election, what 7 + 5 adds to, and how to tie the laces on a pair of shoes. Only autobiographical memory is affected.

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