Dissociative Disorders

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Editor: Deirdre S. Blanchfield
Date: 2016
Publisher: Gale, a Cengage Company
Document Type: Topic overview
Length: 1,563 words

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Dissociative Disorders


Dissociative disorders are a group of mental disorders that affect consciousness, and defined as causing significant interference with the patient's general functioning, including social relationships and employment.


Dissociation is a mechanism that allows the mind to separate or compartmentalize certain memories or thoughts from normal consciousness. These memories are not erased, however, and may resurface spontaneously or be triggered by objects or events in the person's environment.

Dissociation is a process that occurs along a spectrum of severity. Is occurrence does not necessarily mean that a person has a dissociative disorder or other mental illness. A mild degree of dissociation occurs with some physical Page 849  |  Top of Articlestressors; people who have gone without sleep for a long period, been given nitrous oxide for dental surgery, or been in a minor accident often have brief dissociative experiences. Another commonplace example of dissociation is a person's becoming involved in a book or movie so completely that time and place go unnoticed.

Moderate or severe forms of dissociation are caused by such traumatic experiences as childhood abuse, combat, car accidents, criminal attacks, and involvement in a natural disaster. Patients with acute stress disorder, post-traumatic stress disorder (PTSD), or conversion disorder and somatization disorder may develop dissociative symptoms. Recent studies of trauma indicate that the human brain stores traumatic memories in a different way than normal memories. Traumatic memories are not processed or integrated into a person's ongoing life in the same fashion as normal memories. Instead they are dissociated, or detached, and may erupt into consciousness from time to time without warning. The affected person cannot control or influence these memories. Over a period of time, these two sets of memories—the normal and the traumatic—may coexist as parallel sets without being combined or blended. In extreme cases, different sets of dissociated memories may form subpersonalities (called alters) of patients with dissociative identity disorder (formerly called multiple personality disorder).

Dissociative amnesia

Dissociative amnesia is a disorder in which the distinctive feature is the patient's inability to remember important personal information to a degree that cannot be explained by normal forgetfulness. In many cases, it is a reaction to a traumatic accident or witnessing a violent crime. Patients with dissociative amnesia may develop depersonalization or trance states as part of the disorder, but they do not experience a change in identity.

Dissociative fugue, a condition is which a person temporarily loses his or her sense of personal identity and travels to another location where he or she may assume a new identity, is an indicator of dissociative amnesia. This condition usually follows a major stressor or trauma. Apart from inability to recall their past or personal information, patients with dissociative fugue do not behave strangely or appear disturbed to others.

Depersonalization-derealization disorder

Depersonalization-derealization disorder is a disturbance in which the patient's primary symptom is a sense of detachment from the self. Depersonalization as a symptom (not as a disorder) is quite common in college-age populations. It is often associated with sleep deprivation or recreational drug use. It is often accompanied by derealization, where objects in an environment appear altered. Patients sometimes describe depersonalization as feeling like a robot or watching themselves from the outside. Depersonalization disorder may also involve feelings of numbness or loss of emotional “aliveness.”

Dissociative identity disorder (DID)

Dissociative identity disorder (DID) is the newer name for multiple personality disorder (MPD). DID is considered the most severe dissociative disorder and involves all of the major dissociative symptoms.

Dissociative disorder not otherwise specified (DDNOS)

Dissociative disorder not otherwise specified (DDNOS) is a diagnostic category ascribed to patients with dissociative symptoms that do not meet the full criteria for a specific dissociative disorder.


An estimated 2% of people in the United States experience a dissociative disorder. Women are more likely to experience a dissociative episode than men. Nearly half of the adult U.S. population has a depersonalization/derealization experience during their lifetime, but only 2% of these experiences normally qualify as a chronic condition.

Causes and symptoms

The moderate-to-severe dissociation that occurs in patients with dissociative disorders is understood to result from a set of causes:

  • an innate ability to dissociate easily
  • repeated episodes of severe physical or sexual abuse in childhood
  • the lack of a supportive or comforting person to counteract abusive relative(s)
  • the influence of other relatives with dissociative symptoms or disorders

The relationship of dissociative disorders to childhood abuse has led to intense controversy and lawsuits concerning the accuracy of childhood memories. The way the brain stores, retrieves, and interprets memories is still not fully understood. Controversy also exists regarding how much individuals presenting with dissociative disorders have been influenced by books and movies to describe a certain set of symptoms (scripting). Symptoms differ depending on the dissociative condition.

Page 850  |  Top of Article Amnesia

Amnesia in a dissociative disorder is marked by gaps in a patient's memory for long periods or for traumatic events. Doctors can distinguish this type of amnesia from loss of memory caused by head injuries or drug intoxication because the amnesia is “spotty” and related to highly charged events and feelings.


Depersonalization is a dissociative symptom in which the patient feels that his or her body is unreal, changing, or dissolving. Some patients experience depersonalization as being outside their bodies or watching a movie of themselves.


Derealization is a dissociative symptom in which the external environment is perceived as unreal. The patient may see walls, buildings, or other objects as changing in shape, size, or color. In some cases, the patient may feel that other persons are machines or robots, though the patient is able to acknowledge the unreality of this feeling.

Identity disturbances

Patients with dissociative amnesia, DDNOS, or DID often experience confusion about their identities or even assume new identities. Identity disturbances result from the patient's having split off entire personality traits or characteristics as well as memories. When a stressful or traumatic experience triggers the reemergence of these dissociated parts, the patient may act differently, answer to a different name, or appear confused by their surroundings.


When a doctor is evaluating a patient with dissociative symptoms, he or she will first rule out physical conditions that sometimes produce amnesia, depersonalization, or derealization. These physical conditions include epilepsy, head injuries, brain disease, side effects of medications, substance abuse, intoxication, AIDS, dementia complex, or recent periods of extreme physical stress and sleeplessness. In some cases, the doctor may give the patient an electroencephalogram (EEG) to exclude epilepsy or other seizure disorders.

Ifthe patient appears to be physicallynormal, the doctor will rule out psychotic disturbances, including schizophrenia. In addition, doctors can use some psychological tests to narrow the diagnosis. The Dissociative Experiences Scale (DES) is a questionnaire that investigates the dissociative potential of person. If the patient has a high score on this test, they can be evaluated further with the Dissociative Disorders Interview Schedule (DDIS) or the Structured Clinical Interview for DSM-5 Dissociative Disorders (SCID-5). It is also possible for doctors to measure a patient's hypnotizability as part of a diagnostic evaluation.

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A general medical term for loss of memory that is not due to ordinary forgetfulness. Amnesia can be caused by head injuries, brain disease, or epilepsy, as well as by dissociation.
A dissociative symptom in which the patient feels that his or her body is unreal, changing, or dissolving.
A dissociative symptom in which the external environment is perceived as unreal.
A psychological mechanism that allows the mind to split off traumatic memories or disturbing ideas from conscious awareness.
A dissociative experience associated with dissociative amnesia during which a person may be confused about their identity and often wander or travel from their usual home but otherwise appear normal.
The means by which a state of extreme relaxation and suggestibility is induced; used to treat amnesia and identity disturbances that occur in dissociative disorders.
Multiple personality disorder (MPD)—
An older term for dissociative identity disorder (DID).
A disastrous or life-threatening event that can cause severe emotional distress, including dissociative symptoms and disorders.


Treatment of the dissociative disorders often combines several methods.


Patients with dissociative disorders often require treatment by a therapist with some specialized understanding of dissociation. This background is particularly important if the patient's symptoms include identity problems. Many patients with dissociative disorders are helped by group as well as individual treatment.


Some doctors will prescribe tranquilizers or antidepressants for the anxiety and/or depression that often Page 851  |  Top of Articleaccompanies dissociative disorders. Patients with dissociative disorders, however, are at risk of abusing or becoming dependent on medications. There is no drug that can reliably counteract dissociation itself.

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  • How effective is treatment for dissociative disorders?
  • What is the difference between dissociation and dissociative disorders?
  • What are some methods for diagnosing a dissociative disorder?

Hypnosis is used as a method of treatment for dissociative disorders, but the practice is controversial. Hypnosis may help patients recover repressed ideas and memories. Therapists treating patients with DID sometimes use hypnosis in the process of “fusing” the patient's alternate personalities.


Prognoses for dissociative disorders vary. Dissociative amnesia may resolve quickly but can become a chronic disorder in some patients. Depersonalization disorder, DDNOS, and DID are usually chronic conditions. DID usually requires five or more years of treatment for recovery.


Since the primary cause of dissociative disorders is thought to involve extended periods of humanly inflicted trauma, prevention depends on the early elimination of physical and mental abuse.

Parental concerns

Children experiencing a dissociative disorder are at risk of self-harm. Dissociative disorders are often accompanied by suicidal thoughts. Depending on the child's age, he or she also may be at risk of substance abuse, eating disorders, and insomnia. Dissociative disorders can have a negative impact on a child's relationships with family and friends. Parents who suspect their child's behavior could be a dissociative disorder should observe persistent or recurrent behavior and contact a therapist or physician for a diagnosis.



Eisendrath, Stuart J. “Psychiatric Disorders.” In Current Medical Diagnosis & Treatment, 2014. 53rd ed. Edited by Stephen McPhee, et al. McGraw-Hill Medical, 2013.


Dorahy, Martin J., et al. “Dissociation, Shame, Complex PTSD, Child Maltreatment and Intimate Relationship SelfConcept in Dissociative Disorder, Chronic PTSD and Mixed Psychiatric Groups.” Journal of Affective Disorders 172 (2015): 195–203.


American Psychiatric Association. “Highlights of Changes from DSM-IV-TR to DSM-5.” American Psychiatric Association. http://www.dsm5.org/Documents/changes%20from%20dsm-iv-tr%20to%20dsm-5.pdf (accessed July 9, 2015).

Mayo Clinic. “Dissociative Disorders.” Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/dissociative-disorders/basics/definition/con-20031012 (accessed July 9, 2015).

National Alliance on Mental Illness. “Dissociative Disorders.” National Alliance on Mental Illness. https://www.nami.org/Learn-More/Mental-Health-Conditions/DissociativeDisorders (accessed July 9, 2015).


American Psychiatric Association, 1000 Wilson Blvd, Suite 1825, Arlington, VA 22209, (888) 357-7924, apa@psych.org, http://www.psychiatry.org/ .

Rebecca J. Frey, PhD
Revised by Cait Caffrey

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

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Source Citation   

Gale Document Number: GALE|CX3630900256