Dissociative disorders are characterized by disturbances in the integration of mental functions. These disturbances are manifested by loss of memory for personal information or identity, division of consciousness and personality into separate parts, and altered perception of the environment or sense of reality. Table 9-2 lists DSM-IV defined dissociative disorders.
Dissociative Amnesia
In dissociative amnesia, an individual develops a temporary inability to recall important personal information. The amnesia is more extensive than forgetfulness and is not caused by another medical or psychiatric condition (e.g., head trauma). The inability to recall information may take several forms. In localized amnesia, information is lost for a specific time period (e.g., a time associated with trauma). In selective amnesia, some information during a given time period is retained but other information is lost.

In generalized amnesia, personal information is lost for the entire life span. In continuous amnesia, there is an inability to recall information from a single point in time to the present. In systematized amnesia, particular categories of information are lost to retrieval.

Dissociative amnesia is more common in people exposed to trauma, for example, exposure to battle or natural disaster.

Dissociative Fugue
Dissociative fugue is an amnestic disorder characterized by an individual’s sudden unexplained travel away from home, coupled with amnesia for his or her identity. In this condition, patients do not appear mentally ill or otherwise impaired in any other mental function, including memory. In fact, patients are quite capable of negotiating the complexities of travel and interaction with others. In rare cases, an individual will establish a completely new identity in the new home. Dissociative fugue is typically precipitated by a severe trauma or stressor and eventually remits without treatment.

Dissociative Identity Disorder
Dissociative identity disorder (formerly called multiple personality disorder) is a controversial diagnosis in psychiatry. The diagnosis of dissociative identity disorder requires the presence of two or more separate personalities (alters) that recurrently take control of an individual’s behavior. Individuals with this disorder often have amnesia for important personal information (also known as “losing time”). The various personalities (the average number by available surveys is seven distinct personalities) may be unaware of each other’s existence and thus may be quite confused as to how they arrived at certain places or why they cannot recall personal events. At other times, one or more personalities may be aware of the others, a condition known as coconsciousness.

Some personalities may display conversion symptoms or self-mutilating behavior. The alters may be of varying ages and different genders and demeanors.

Dissociative identity disorder is most common in females and has a chronic course. Individuals with dissociative identity disorder are highly suggestible and easily hypnotized. Most report a childhood history of severe physical or sexual abuse. Satanic or cult abuse reports are also common. In many cases, these reports of abuse cannot be verified, leading many clinicians to believe that individuals with dissociative identity disorder may suffer from memories of events that did not occur. Whether these memories are true or false, they cause a great deal of suffering.

Disagreement over the very nature of dissociative identity disorder has led to divergent treatment opinions. Some clinicians believe that ignoring the different personalities will cause them to recede, based on the notion that the easy suggestibility of these patients will lead to reinforcement of alters if they are discussed. Others believe that long-term psychotherapy, exploring the various personalities and integrating them into a whole person, is the treatment of choice.

Depersonalization Disorder
Depersonalization disorder is characterized by “persistent or recurrent experiences of feeling detached from and as if one is an outside observer of one’s mental processes or body” (DSM-IV). Individuals with this disorder may complain of a sense of detachment, of feeling mechanical or automated, and of absence of affect or sensation. Individuals with depersonalization disorder are easily hypnotized and prone to dissociate.