Definition: Dissociative identity disorder (DID), previously referred to as multiple personality disorder, involves a disturbance of identity in which two or more separate and distinct personality states (or identities) control an individual’s behavior at different times. When under the control of one identity, a person is usually unable to remember some of the events that occurred while other personalities were in control. The different identities, referred to as alters, may exhibit differences in speech, mannerisms, attitudes, thoughts and gender orientation. The alters may even present physical differences, such as allergies, right-or-left handedness or the need for eyeglass prescriptions. Stress or a reminder of a trauma can act as a trigger to bring about a “switch” of alters. This can create a chaotic life and cause problems in work and social situations.

Symptoms: Symptoms of DID can include the following:

  • Changing levels of functioning, from highly effective to nearly disabled
  • Severe headaches or pain in other parts of the body
  • Depersonalization (episodes of feeling disconnected or detached from one’s body and thoughts)
  • Derealization (perceiving the external environment as unreal)
  • Depression or mood swings
  • Unexplained changes in eating and sleeping patterns
  • Anxiety, nervousness, or panic attacks
  • Problems functioning sexually
  • Suicide attempts or self-injury
  • Substance abuse
  • Amnesia (memory loss) or a sense of “lost time”
  • Hallucinations (sensory experiences that are not real, such as hearing voices)

Causes: Dissociation is a common, naturally occurring defense against childhood trauma. When faced with overwhelming abuse, children can dissociate from full awareness of a traumatic experience. Dissociation may become a defensive pattern that persists into adulthood and can result in a full-fledged dissociative disorder.

It is generally accepted that DID results from extreme and repeated trauma that occurs during important periods of development during childhood, usually not past the age of five. The trauma often involves severe emotional, physical or sexual abuse, but also might be linked to a natural disaster or war. An important early loss, such as the loss of a parent, also might be a factor in the development of DID. In order to survive extreme stress, the person separates the thoughts, feelings and memories associated with traumatic experiences from their usual level of conscious awareness.