In dissociative identity disorder, formerly called multiple personality disorder, two or more identities or personalities alternate.

Dissociative identity disorder appears to be a rather common mental disorder. It can be found in 3 to 4% of people hospitalized for other mental health disorders and in a sizable minority of people in drug abuse treatment facilities. However, some authorities believe that many cases of this disorder reflect the influence of therapists on suggestible people.

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.

Human development requires that children be able to integrate complicated and different types of information and experiences. As children learn to achieve a cohesive, complex identity, they go through phases in which different perceptions and emotions of themselves and others are kept segregated. These different perceptions and emotions become involved in the generation of different selves, but not every child who suffers abuse or a major loss or trauma has the capacity to develop multiple personalities. Those who do have the capacity also have normal ways of coping, and most of these vulnerable children are sufficiently protected and soothed by adults, so dissociative identity disorder does not develop.

Dissociative Identity Disorder and Childhood Abuse About 97 to 98% of adults with dissociative identity disorder report having been abused during childhood. Abuse can be documented for 85% of the adults and 95% of the children and adolescents with dissociative identity disorder. Although childhood abuse is a major cause of dissociative identity disorder, that does not mean all the specific abuses alleged by people with this disorder really happened. Some aspects of some reported experiences clearly are not accurate. In addition, some people were not abused at all, but rather, suffered an important early loss, such as the death of a parent, a serious physical illness, or some other very stressful experience.

Symptoms

People with dissociative identity disorder often describe an array of symptoms that can resemble those of other mental health disorders as well as many physical disorders. Some symptoms are an indication that another disorder is indeed present, but some symptoms may reflect the intrusions of past experiences into the present. For example, sadness may indicate coexisting depression, or it may be that one of the personalities is reliving emotions associated with past misfortunes.

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.

People with dissociative identity disorder 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." While most people cannot recall much about the first 3 to 5 years of life, people with dissociative identity disorder may have considerable amnesia for the period between the ages of 6 and 11 as well.

Diagnosis

To make the diagnosis of dissociative identity disorder, a doctor conducts a thorough psychologic interview. A medical examination may be needed to determine if a physical disorder is present that would explain certain symptoms. Special questionnaires have been developed to help doctors identify dissociative identity disorder.

Interviews may need to be prolonged and involve careful use of hypnosis or drug facilitation (see Amnesia and Related Disorders: Treatment and Prognosis). Hypnosis or drug-facilitated interviews may make the person more likely to allow the doctor to encounter other personalities or to reveal information about a period for which there is amnesia. However, some doctors feel that hypnosis and drug-facilitated interviews should not be performed because they believe the techniques can themselves generate symptoms of dissociative identity disorder.

Treatment and Prognosis

Some symptoms may come and go (fluctuate) spontaneously, but dissociative identity disorder does not clear up on its own. 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 arduous and emotionally painful. The person 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 the person 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. Hypnosis may be helpful.

The prognosis of people with dissociative identity disorder depends on the symptoms and features they experience. For example, people who have additional serious mental health disorders, such as personality disorders, mood disorders, eating disorders, and substance abuse disorders, have a poorer prognosis.

Last full review/revision February 2003