Dissociative identity disorder

Dissociative identity disorder is defined in the DSM-IV-TR as the presence of two or more personality states or distinct identities that repeatedly take control of one’s behavior. The patient has an inability to recall personal information. The extent of this lack of recall is too great to be explained by normal forgetfulness. The disorder cannot be due to the direct physical effects of a general medical condition or substance.

DID entails a failure to integrate certain aspects of memory, consciousness and identity. Patients experience frequent gaps in their memory for their personal history, past and present. Patients with DID report having severe physical and sexual abuse, especially during childhood. The reports of patients with DID are often validated by objective evidence.

Physical evidence may include variations in physiological functions in different identity states, including differences in vision, levels of pain tolerance, symptoms of asthma, the response of blood glucose to insulin and sensitivity to allergens. Other physical findings may include scars from physical abuse or self-inflicted injuries, headaches or migraines, asthma and irritable bowel syndrome.

DID is found in a variety of cultures around the world. It is diagnosed three to nine times more often in adult females than males. Females average 15 or more identities, males eight identities. The sharp rise in the reported cases of DID in the U.S. may be due the greater awareness of DID’s diagnosis, which has caused an increased identification of those that were previously undiagnosed.

The average time period from DID’s first presentation of symptoms to its diagnosis is six to seven years. DID may become less manifest as patients reach past their late 40’s, but it can reemerge during stress, trauma or substance abuse. It is suggested in several studies that DID is more likely to occur with first-degree biological relatives of people that already have DID, than in the regular population.

Symptomology
Individuals diagnosed with DID demonstrate a variety of symptoms with wide fluctuations across time; functioning can vary from severe impairment in daily functioning to normal or high abilities.

Patients may experience an extremely broad array of other symptoms that resemble epilepsy, schizophrenia, anxiety disorders, mood disorders, post traumatic stress disorder, personality disorders, and eating disorders.

Causes
The causes of dissociative identity disorder are theoretically linked with the interaction of overwhelming stress, traumatic antecedents, insufficient childhood nurturing, and an innate ability to dissociate memories or experiences from consciousness. Prolonged child abuse is frequently a factor, with a very high percentage of patients reporting documented abuse often confirmed by objective evidence. The Diagnostic and Statistical Manual of Mental Disorders states that patients with DID often report having a history of severe physical and sexual abuse. The reports of patients suffering from DID are "often confirmed by objective evidence," and the DSM notes that the abusers in those situations may be inclined to "deny or distort” these acts. Research has consistently shown that DID is characterized by reports of extensive childhood trauma, usually child abuse.   Dissociation is recognized as a symptomatic presentation in response to psychological trauma, extreme emotional stress, and in association with emotional dysregulation and borderline personality disorder.

DMS inclusion
DID meets all of the guidelines for inclusion in the DSM and is supported by taxometric research. Research has established DID as a valid diagnosis. In one study, DID was found to be a genuine disorder with a constant set of core features.

History
The 19th century saw a number of reported cases of multiple personalities which Rieber estimated would be close to 100.

By the late 19th century there was a general realization that emotionally traumatic experiences could cause long-term disorders which may manifest with a variety of symptoms. Between 1880 and 1920, many great international medical conferences devoted a lot of time to sessions on dissociation.

Starting in about 1927, there was a large increase in the number of reported cases of schizophrenia, which was matched by an equally large decrease in the number of multiple personality reports. Bleuler also included multiple personality in his category of schizophrenia. It was found in the 1980s that MPD patients are often misdiagnosed as suffering from schizophrenia. Multiple personality disorder began to emerge as a separate disorder in the 1970s when an initially small number of clinicians worked to re-establish MPD as a legitimate diagnosis.