Multiple Personality Disorder

Fifty-nine to ninety-eight percent of people diagnosed with multiple personality disorder were either physically or sexually abused as children. Many times when a young child is subjected to abuse, he or she splits off from what is happening, becoming so detached that what is happening may seem more like a movie or television show than reality. This self-hypnotic state, called disassociation, is a defense mechanism that protects the child from thinking and feeling overwhelmingly intense emotions. Disassociation walls these thoughts and emotions off so that the child is unaware of them. In effect, they become secrets, even from the child. According to the American Psychiatric Association, many MPD patients cannot remember much of their childhoods.

Not all children who are severely and repeatedly abused develop multiple personality disorder, but if the sexual or physical abuse is extreme and repeated, disassociated clusters of thoughts and feelings may begin to take on lives of their own, especially when the child has no time or space in which to emotionally recover between abuses. Each cluster tends to have a common emotional theme such as anger, sadness, or fear. Eventually, as the walls of disassociation thicken, these clusters develop into full-blown personalities, each with its own memory and characteristics.

Some researchers believe the reason some abused children develop MPD may have a biological basis. Studies of how brain chemistry affects memory indicate that when an intensely traumatic experience occurs, the brain's neurochemicals may be released in such large amounts they influence the area of the brain responsible for memory to pigeonhole what is remembered into separate compartments. Depending on their individual brain chemistry, some human beings may be better able to disassociate than others. About a third of people with MPD have complex partial seizures of the right temporal lobe of the brain. Some researchers think this form of epilepsy might also affect memory and be yet another cause for the disorder.

Although some studies show that the illness may be more common in first-generation relatives of MPD patients, there is no proof the disorder is inherited.