Dissociative identity disorder

Dissociative identity disorder is a psychiatric diagnosis, most recently defined in the text revision of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). It is the existence in an individual of two or more distinct personalities or ego-states, each with its own pattern of perceiving and interacting with the environment. To qualify as dissociative identity disorder (multiple personality disorder), at least two personalities must routinely take alternate control of the individual's behavior, and there must be a loss of memory that goes beyond normal forgetfulness. This memory loss is often referred to as "switching". These symptoms must occur independently of substance abuse or a general medical condition.

Dissociative identity disorder is also known as multiple personality disorder (MPD) as described in the tenth edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10). In North America, the American Psychiatric Association changed the name to dissociative identity disorder for the DSM due to the degree of controversy in the psychiatric and psychological communities there regarding the concept of one (physical) individual having more than one personality, where personality may be defined as the sum total of that (physical) individual's mental states.

While dissociation is a demonstrable psychiatric condition that is tied to several different disorders, specifically those involving early childhood trauma and anxiety, multiple personality remains controversial (see multiple personality controversy). Despite the controversy, many mental health institutes, such as McLean Hospital, have wards specifically designated for dissociative identity disorder.

Symptoms of Dissociative Identity Disorder include a type of psychogenic amnesia (no medical cause, only psychological). Through this amnesia the person is able to repress memories of traumatic event/s or a period of time. This is a fragmentation of self and experience of the past. Through having several alters the host personality is living through healthy alters, aggressive alters, and often alters that are children. The therapy for this disorder is usually long-term.

Two characteristics of DID are depersonalization and derealization. Depersonalization is the distortion in the perception of self and one's reality. This person will often appear to be detached from reality. Patients often refer to this as "feeling outside of their body and being able to observe it from a distance". Derealization is the distortion in the perception of others. Through derealization, others will not seem to be real to the person. To these patients others may look the same and sound the same, but their real identity is absent or has differed in some way.

Research has shown that patients with Dissociative Identity Disorder often hide their symptoms around others. The average number of alters is 15 and the onset is usually in early childhood, which is why some of a patient's alters are often children. Many patients have co-morbidity, which means that they also have another disorder, for example, generalized anxiety disorder.