Dissociative identity disorder, which used to be called multiple personality disorder, is one of the dissociative disorders listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Dissociative disorders all have a central feature of "dissociation,” or a disruption in the normal integrated functions of consciousness, memory, identity and perception.
What is Dissociative Identity Disorder?
In dissociative identity disorder (DID), the individual experiences the presence of two or more distinct identities or personalities (also sometimes called “alters”). These personalities or alters recurrently take control of the person’s behavior, and the person often experiences a loss of memory for what happened while another personality or alter was in control.
Prevalence of Dissociative Identity Disorder
Dissociative identity disorder is a very rare condition. It is so rare that it is difficult to study; little research has been conducted on people with DID. One study found that about 1% of women in the community have DID, but more studies are needed to confirm this finding. There has been a recent surge in the diagnosis of DID; however, it is not clear whether this is due to a greater awareness of the disorder by mental health professionals or to overdiagnosis.
The Dissociative Identity Disorder Controversy: Does DID Exist?
There has long been controversy within the field of mental health about whether DID exists. There is evidence that people with DID are more susceptible to hypnosis and suggestibility; this has led some experts to argue that the separate identities experienced by people with DID may be the result of suggestion.
Other experts, however, argue that there are some recent studies that refute that argument. For example, some studies have demonstrated that the different personalities of a person with DID have different physiological profiles (e.g., different brain activation patterns or cardiovascular responses), or different memories. These studies have been used as evidence for the existence of actual alters. Studies on DID are limited, and it remains a controversial diagnosis. However, the diagnosis is now gaining more acceptance in the mental health community, and we are learning more about how to treat DID.
Diagnostic Criteria for Dissociative Identity Disorder
The diagnostic criteria for dissociative identity disorder (as specified in the DSM-IV), are as follows:
- The presence of two or more distinct identities of personalities states, each with its own pattern of interpreting, relating to, and thinking about the environment and the self
- At least two of these identities or personality states recurrently take control of the person’s behavior
- Inability to recall important personal information that is too extensive to be explained by ordinary forgetfulness
- The symptoms not due to the effects of a substance or medical condition (and, in children, the symptoms are not attributable to imaginary playmates or other fantasy play)
Dissociative Identity Disorder, Borderline Personality Disorder and Other Related Conditions
People with DID often report the experience of severe physical and sexual abuse during childhood and also frequently have concurrent symptoms of borderline personality disorder (BPD), including self-harming behaviors, impulsivity and instability in relationships. This may be related to the fact that childhood abuse is a risk factor both for dissociative identity disorder and borderline personality disorder.
One theory about the development of DID proposes that people with DID have experienced a psychological trauma so severe that the only way to manage that trauma is to develop very strong dissociation as a coping mechanism. Over time, chronic dissociation leads to the formation of different identities. While dissociation is also a symptom of borderline personality disorder, usually the dissociation seen in BPD does not happen as frequently or as severely as in DID (i.e., other personalities do not emerge). Someone with the symptoms of DID and BPD may receive a diagnosis of both disorders.
People with DID may experience other trauma-related symptoms, including nightmares, flashbacks or other symptoms characteristic of post-traumatic stress disorder (PTSD).
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR Fourth Edition. 4th ed. American Psychiatric Publishing: Washington DC, 2000.
Merckelbach H, Devilly GJ, Rassin E. “Alters in Dissociative Identity Disorder Metaphors or Genuine Entities?” Clinical Psychology Review. 22:481-498, 2002.
Sar V, Akyüz G, Dogan O. “Prevalence of Dissociative Disorders Among Women in the General Population.” Psychiatry Research. 149:169-176, 2007