Multiple Personality Disorder (MPD)
Multiple personality disorder (MPD) is a psychiatric disorder characterized by having at least one “alter” personality that controls behavior. The “alters” are said to occur spontaneously and involuntarily, and function more or less independently of each other. The unity of consciousness, by which we identify our selves, is said to be absent in MPD.
In order to understand multiple personality it is first important to eliminate a popular misconception. Many people confuse multiple personality with schizophrenia. However, schizophrenia is an entirely different disorder and does not have anything to do with multiple personality. One characteristic of schizophrenia is a “split” between thinking and affect (feelings) which results in an inappropriate expression of affect.
The basic theoretical dynamic in multiple personality is that the person deals with conflicting feelings and thoughts by repressing them and compartmentalizing them so that certain kinds of feelings and thoughts are expressed in one personality or state of consciousness, and other conflicting feelings and thoughts are expressed in another personality, making it unnecessary to reconcile the different thoughts and feelings.
There is general agreement that the cause of MPD is repressed memories of childhood sexual abuse. The evidence for this claim has been challenged, however, and there are very few reported cases of MPD afflicting children.
Psychologist Nicholas P. Spanos argues that repressed memories of childhood abuse and multiple personality disorder are “rule-governed social constructions established, legitimated, and maintained through social interaction.” In short, Spanos argues that most cases of MPD have been created by therapists with the cooperation of their patients and the rest of society – the self and the multiple selves of the MPD patient are social constructs, not needing a metaphysical or biological explanation so much as a social-psychological one.
There is probably no greater divide in the professional world than that regarding the authenticity and diagnosis of this disorder. It ranges from those who insist there is no such phenomenon to those who believe every reported case is genuine and we have not yet begun to uncover them all. In part, the disagreement centers on the more foundational issue of repressed and recovered memory of trauma, which itself has moved through different fads.
If you want to conduct your own research to find out more about multiple personality disorder and some other psychological disorders, these two links should get you started: Skeptic’s Dictionary and Psychological Disorders