Multiple Personalities: Crime and Defense
Dissociative Identity Disorder
Among mental health professionals, the diagnosis of dissociative identity disorder (DID) is the name given in the American Psychiatric Associations Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (1994) for what used to be called multiple personality disorder (added to the DSM-III in 1980). Prior to that, it was just known as a hysterical dissociative condition, with no coded diagnosis.
The diagnosis of multiple personalities in a single body has been confused with schizophrenia as a split personality (a common misunderstanding of this psychotic condition). The idea of MPD is that a person has fractured into several alter personalities and that two or more sub-personalities share a single body, each with its own identity, and each takes turns controlling the personality and behavior. They emerge as a result of trauma (even this is disputed), usually sexual abuse and usually occurring before the age of 5, and may trap certain parts of the personality at the age during which the trauma occurred.
To some extent, as some experts have written, the alters arise to protect the person from overwhelming memories, as well as to protect the persons secrets from outsiders. Some alters appear to form from forbidden impulses as well.
An unusual example of this condition was shown on the A&E documentary, The Unexplained.
In DID, according to some theories, the "core" or primary person generally experiences periods of amnesia and may even find himself or herself in a foreign place with no idea how they arrived. This is called an amnesic barrier between identities. One "person" may have full access to the memory bank, while others get only partial access, and some may be altogether unaware of the others.
In some cases, the sub-personalities know which one the controlling or core personality is. While undergoing trauma, they learned to dissociateto mentally remove themselves from full awareness of the situationand this form of psychological flight then becomes a survival mechanism. This is thought to disturb the normal integrative functions of identity and memory. Poly-fragmented DID, say some therapists, may involve several hundred different identities in a single body.
Often those who suffer from MPD, say advocates, do not even realize it. The condition is commonly diagnosed through recovered memory therapy, in which the patient is found to have repressed trauma. Experts on this personality disturbance say a hidden memory may still emerge in symptoms such as depression, numbness, hypersensitivity, and over-reactions to certain environmental triggers. DID sufferers may also experience vague flashbacks, or the memory might recur spontaneously many years after the incident. These people may "trance out," feel out of touch with reality, ignore genuine pain, and experience sudden panic attacks. They may also have eating disorders, be abusive to others or themselves, or acquire serious addictions. Generally, they have trouble with intimacy in relationships and may experience sleep disturbances.
A mental health practitioner trying to determine whether this disorder is present would begin with a clinical interview to check if there are memories of childhood abuse or stretches of time the subject cannot recall. The questions include ways to assess the presence of the array of MPD symptoms, and some type of structured diagnostic test might be utilized. Among these are the Dissociative Experiences Scale (DES) and the Dissociative Interview Schedule (DDIS). Therapists also try to collect data from people who have seen the subject in an altered personality stategetting corroborating information to compare against the subjects memories.
While other personalities can be elicited through hypnosis, it's also possible to affect a suggestible person with hypnosis in such a way that they will act as if they have different personalitiesespecially if they have something to gain. In fact, some critics insist alter personalities are nothing more than social constructs, suggested by a therapist to a vulnerable patient and supported by the social milieu (including insurance payments). In short, there is no clear consensus among professionals on the disorder.
Lets revisit the two most recognizable cases to see how they influenced the development of the diagnosis.