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Dissociative Identity Disorder

(Multiple Personality Disorder)


David Spiegel

, MD, Stanford University School of Medicine

Reviewed/Revised May 2023

In dissociative identity disorder, formerly called multiple personality disorder, two or more identities alternate being in control within the same person. These identities may have speech, temperamental, and behavioral patterns that are different from those normally associated with the person. Also, the person cannot recall information that would ordinarily be readily remembered, such as everyday events, important personal information, and/or traumatic or stressful events.

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

  • People have two or more identities and have gaps in their memory for everyday events, important personal information, and traumatic or stressful events, as well as many other symptoms, including depression and anxiety.

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

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

Dissociative identity disorder is rare, and the number of people who have it is unknown.

Dissociative identity disorder has the following forms:

  • Possession

  • Nonpossession

In the possession form, the person's different identities appear to be outside agents who have taken control of the person. This outside agent may be described as a supernatural being or spirit (often a demon or god, who may demand punishment for past actions) but sometimes is another person (often someone who has died, sometimes in a dramatic fashion). In all cases, people speak and act very differently from the way they normally do. Thus, the different identities are obvious to other people. In many cultures, similar possession states are a normal part of the local culture or religion and are not considered a disorder. In contrast, in dissociative identity disorder, the alternate identity is unwanted, causes substantial distress and impairment, and appears in times and places that are inappropriate for the person's social situation, culture, and/or religion.

Nonpossession forms tend to be less apparent to others, although they may display a sudden shift in affect or interpersonal manner. People may feel a sudden alteration in their sense of self, perhaps feeling as though they were observers of their own speech, emotions, and actions, rather than the agent.

Causes of Dissociative Identity Disorder

Dissociative identity disorder usually occurs in people who experienced overwhelming stress or trauma during childhood. In the United States, Canada, and Europe, about 90% of people with this disorder have a history of severe abuse (physical, sexual, or emotional) or neglect during childhood. Some people have not been abused but have experienced an important early loss (such as death of a parent), a serious medical illness, or other overwhelmingly stressful events.

As children develop, they must learn to integrate complicated and different types of information and experiences into a cohesive, complex personal identity. Sexual and physical abuse that occurs in childhood when personal identity is developing may have lasting effects on the person's ability to form a single, unified identity, especially when the abusers are parents or caregivers.

Children who are abused may go through phases in which different perceptions, memories, and emotions of their life experiences are kept segregated. This segregation of experiences is intensified by parents or other caretakers who behave inconsistently over time (for example, being by turns affectionate or abusive), a behavior that is called betrayal trauma. Over time, such children may develop an increasing ability to escape the abuse by "going away," by detaching themselves from their harsh physical environment, or by retreating into their own mind. Each phase or traumatic experience may be used to produce a different identity.

However, if such vulnerable children are sufficiently protected and soothed by truly caring adults, dissociative identity disorder is less likely to develop.

Symptoms of Dissociative Identity Disorder

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

Several symptoms are typical of dissociative identity disorder.


Amnesia may involve the following:

  • Gaps in the memory of past personal events: For example, people may not remember certain periods of time during childhood or adolescence.

  • Lapses in memory of current everyday events and well-learned skills: For example, people may temporarily forget how to use a computer.

  • Discovery of evidence of things that they have done but have no memory of doing.

People may sense that they are missing—or have lost—a period of time.

After an episode of amnesia, people may discover objects in their closet at home 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. They may be told they said or did things that they cannot remember.

More than one identity

In the possession form, the different identities are readily apparent to family members and other observers. The person speaks and acts in an obviously different manner, as though another person or being has taken over.

In the nonpossession form, the different identities are often not as apparent to observers, although the person may display a sudden shift in how they behave and relate to others. Instead of acting as if another being has taken them over, people with this form of dissociative identity disorder may feel detached from aspects of themselves (a condition called depersonalization Depersonalization/Derealization Disorder Depersonalization/derealization disorder involves a persistent or recurring feeling of being detached from one’s body or mental processes, like an outside observer of one's life (depersonalization)... read more ), as if they were watching themselves in a movie or as though they were seeing a different person. They may suddenly think, feel, say, and do things that they cannot control and that do not seem to belong to them. Attitudes, opinions, and preferences (for example, regarding food, clothing, or interests) may suddenly change, then change back. Some of these symptoms, such as changes in food preferences, can be observed by others.

People may think that their body feels different (for example, like that of a small child or someone of the opposite sex) and that their body does not belong to them. They may refer to themselves in the first person plural (we) or in the third person (he, she, they), sometimes without knowing why.

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 identities interact with each other, affected people may report hearing voices. The voices may be internal conversations among the identities or may address the person directly, sometimes commenting on the person's behavior. Several voices may speak at the same time and be very confusing.

People with dissociative identity disorder also experience intrusions of identities, voices, or memories into their everyday activities. For example, at work, an angry identity may suddenly yell at a coworker or boss.

Other symptoms

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 general medical disorders. For example, they often develop severe headaches or other aches and pains. 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 Depression Depression is a feeling of sadness and/or a decreased interest or pleasure in activities that becomes a disorder when it is intense enough to interfere with functioning. It may follow a recent... read more , but it also may indicate that one of the personalities is reliving emotions associated with past misfortunes.

Many people with dissociative identity disorder are depressed and anxious. They are prone to injuring themselves. Substance use disorders Overview of Substance-Related Disorders Medications and other substances, whether used for legitimate medical purposes, as a habit (for example, caffeine), or recreationally, are an integral part of everyday life for many people ... read more , episodes of self-mutilation Nonsuicidal Self-Injury (NSSI) Nonsuicidal self-injury is a self-inflicted act that causes pain or superficial damage but is not intended to cause death. Although the methods people use to hurt themselves, such as cutting... read more , and suicidal behavior Suicidal Behavior Suicide is death caused by an act of self-harm that is intended to be lethal. Suicidal behavior includes completed suicide, attempted suicide, and suicidal ideation (thoughts and ideas). Suicide... read more (thoughts and attempts) are common, as is sexual dysfunction (see Sexual Dysfunction in Men Overview of Sexual Function and Dysfunction in Men In men, sexual dysfunction refers to difficulties engaging in sexual intercourse. Sexual dysfunction encompasses a variety of disorders that affect Sex drive (libido) The ability to achieve... read more and Sexual Dysfunction in Women Overview of Sexual Function and Dysfunction in Women Sexual dysfunction in women includes pain during intercourse, involuntary painful contractions (spasms) of the muscles around the vagina (vaginismus), lack of interest in sex (low libido), and... read more ). Like many people with a history of abuse, they may seek out or stay in dangerous situations and are vulnerable to retraumatization.

In addition to hearing voices of other identities, people may have other types of hallucinations (of sight, touch, smell, or taste). The hallucinations may occur as part of a flashback. Thus, dissociative identity disorder may be misdiagnosed as a psychotic disorder such as schizophrenia Schizophrenia Schizophrenia is a mental disorder characterized by loss of contact with reality (psychosis), hallucinations (usually, hearing voices), firmly held false beliefs (delusions), abnormal thinking... read more . However, these hallucinatory symptoms differ from the typical hallucinations of psychotic disorders. People with dissociative identity disorder experience these symptoms as coming from an alternate identity, from inside their head. For example, they may feel as if someone else is wanting to cry using their eyes. People with schizophrenia usually think the source is external, outside of themselves.

Often, people try to hide or downplay their symptoms and the effect they have on others.

Diagnosis of Dissociative Identity Disorder

  • A doctor's evaluation, based on specific diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR)

Doctors diagnose dissociative identity disorder based on the person's history and symptoms:

  • People have two or more identities, and their sense of being themselves and of being able to act as themselves is disrupted.

  • They have gaps in their memory for everyday events, important personal information, and traumatic events—information that would not typically be forgotten.

  • They are very distressed by their symptoms, or their symptoms make them unable to function in social situations or at work.

Doctors conduct a thorough psychiatric interview and use special questionnaires developed to help identify dissociative identity disorder and to rule out other mental health disorders. A physical examination and laboratory tests may be needed to determine whether people have a medical 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 medication-facilitated interview). People may also be asked to keep a journal between doctor's visits. These measures may allow doctors to encounter other identities or make the person more likely to reveal information about a forgotten period of time.

Doctors may also attempt to directly contact other identities by asking to speak to the part of the mind involved in behaviors that people cannot remember or that seem to be done by someone else.

Doctors can usually distinguish dissociative identity disorder from malingering (faking physical or psychologic symptoms to obtain a benefit). Malingerers do the following:

  • Tend to overreport well-known symptoms of the disorder and underreport others

  • Tend to create stereotypical alternate identities

  • Usually seem to enjoy the idea of having the disorder (people with dissociative identity disorder often try to hide it)

If doctors suspect that the disorder is faked, doctors can also cross-check information from several sources to check for inconsistencies that rule out dissociative identity disorder.

Treatment of Dissociative Identity Disorder

  • Supportive care, including medications as needed for associated symptoms

  • Psychotherapy

  • Sometimes guided imagery and hypnosis

The goal of treatment for dissociative identity disorder 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.

Psychotherapy is often long, arduous, and emotionally painful. People may experience many emotional crises from the actions of the identities 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. During hospitalization, people are continuously given support and monitored.

Key components of effective psychotherapy for dissociative identity disorder include the following:

  • Providing a way to stabilize intense emotions

  • Negotiating relationships between identity states

  • Working through traumatic memories

  • Protecting against further victimization

  • Establishing and enhancing a good relationship between the person and the therapist

Sometimes psychotherapists use techniques such as hypnosis Hypnotherapy Hypnotherapy is a type of mind-body medicine. In hypnotherapy (hypnosis), people are guided into an advanced state of relaxation and heightened attention. Hypnotized people become absorbed in... read more to help such people calm themselves, alter their perspective on the events, and gradually desensitize the effects of traumatic memories, which are sometimes tolerated only in small amounts. Hypnosis can sometimes help people learn to access their identities, to facilitate communication between them, and to control the shifts between them.

Prognosis for 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 and the quality and duration of treatment they receive. 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.

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