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Dissociative Identity Disorder

by Daphne Simeon, MD

In dissociative identity disorder, formerly called multiple personality disorder, two or more identities alternate within the same person.

  • Extreme stress during childhood may prevent some children from integrating their experiences into one cohesive identify.

  • People have several personalities that may or may not know about and interact with each other, as well as many other symptoms, including severe headaches, memory gaps, and a tendency toward self-harm.

  • A thorough psychologic interview and special questionnaires, sometimes facilitated by hypnosis or sedatives, help doctors diagnose the disorder.

  • Extensive psychotherapy may help people integrate their personalties or at least help the personalities cooperate.

About 1% of people may have dissociative identity disorder.


Dissociative identity disorder appears to be caused by the interaction of several factors. They include the following:

  • Overwhelming stress

  • An ability to separate memories, perceptions, or identity from conscious awareness

  • Abnormal psychologic development

  • Insufficient protection and nurturing during childhood

As children develop, they must learn to integrate complicated and different types of information and experiences into a cohesive, complex identity. Children who are abused or experience a major loss or trauma may go through phases when they keep different emotions and perceptions of themselves and others separate. This separation may lead to the development of multiple personalities. However, most of these vulnerable children are sufficiently protected and soothed by adults, so dissociative identity disorder does not develop.


People with dissociative identity disorder often describe an array of symptoms that can resemble those of other mental health disorders as well as those of many physical disorders. For example, they often develop severe headaches or other aches and pains and may experience sexual dysfunction. Different groups of symptoms occur at different times. Some of these symptoms may indicate that another disorder is present, but some may reflect the intrusion of past experiences into the present. For example, sadness may indicate coexisting depression, but it also may indicate that one of the personalities is reliving emotions associated with past misfortunes.

People are prone to injuring themselves. Substance abuse, episodes of self-mutilation, and suicide attempts are common. Some people remain deeply attached to the people who have abused them.

Some of a person’s personalities are aware of important personal information of which 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, and so on with other personalities present.

The switching of personalities and the lack of awareness of the behavior of the other personalities often make life chaotic. Because the personalities often interact with each other, affected people may report hearing internal conversations among the personalities or hearing the voices of other personalities commenting on their behavior or addressing them.

Affected people experience distortion of time, with time lapses and amnesia. After an episode of amnesia, they may discover objects or samples of handwriting that they cannot account for or recognize. They may also find themselves in different places from where they last remember being and have no idea why or how they got there. They may not be able to recall things they have done or account for changes in their behavior. Often, they refer to themselves as “we,” “he,” or “she” and may not know why. Most people cannot recall much about the first 3 to 5 years of life, but people with dissociative identity disorder may not recall much about the period between the ages of 6 and 11 as well.

People with the disorder may feel detached from themselves (depersonalization) and experience familiar people and surroundings as if they were unfamiliar, strange, or unreal (derealization). They are often concerned about issues of control, both self-control and the perceived control over others.

Dissociative identity disorder is chronic and potentially disabling or fatal, although many people function very well and lead creative and productive lives.


Doctors conduct a thorough psychologic interview and use special questionnaires developed to help identify dissociative identity disorder. A medical examination may be needed to determine whether people have a physical disorder that would explain certain symptoms.

Interviews may need to be long and involve careful use of hypnosis or a sedative given intravenously to relax the person (a drug-facilitated interview). The sedative may allow doctors to encounter other personalities or make the person more likely to reveal information about a forgotten period of time. However, some doctors feel that hypnosis and drug-facilitated interviews should not be used because the techniques themselves may cause symptoms of dissociative identity disorder.


Some symptoms may come and go spontaneously, but dissociative identity disorder does not clear up on its own. How well people recover depends on the symptoms and features they have. For example, people who have other serious mental health disorders, who do not function well in life, or who remain deeply attached to their abusers do less well. They may require treatment longer, and treatment is less successful.


The goal of treatment is usually to integrate the personalities into a single personality. However, integration is not always possible. In these situations, the goal is to achieve a harmonious interaction among the personalities that allows more normal functioning.

Drug therapy can relieve some specific coexisting symptoms, such as anxiety or depression, but does not affect the disorder itself.

Psychotherapy is often long, arduous, and emotionally painful. People may experience many emotional crises from the actions of the personalities and from the despair that may occur when traumatic memories are recalled during therapy. Several periods of psychiatric hospitalization may be necessary to help people through difficult times and to come to grips with particularly painful memories. Generally, two or more psychotherapy sessions a week for at least 3 to 6 years are necessary.