What Causes Multiple Personality Disorder?

Multiple personality disorder, also known as dissociative personality disorder, is one of a number of recognized personality disorders. This disorder can be caused by severe emotional trauma, commonly trauma that was sustained during childhood. This mental health illness also can have biological causes, such as the organic damage sustained by the brain because of conditions such as temporal lobe epilepsy, sensory deprivation and Alzheimer's disease. Multiple personality disorder also might occur after epilepsy surgery, when the corpus callosum, which connects the right and left halves of the brain, is severed to reduce the symptoms and neurological damage associated with severe epilepsy.

Trauma-related multiple personality disorder is described as an emotional personality disorder. Often, a child with this disorder has endured severe psychological trauma, usually in the form of physical or sexual abuse, but it can include instances of the child being exposed to, or witnessing acts of, extreme violence. Children who experience severe trauma may dissociate themselves from the painful and terrifying reality that surrounds them, so that to their young minds, the traumatic events will seem more like a television show than real life. The mind adopts the dissociation technique as a defensive mechanism, partitioning and separating the painful memories, often suppressing them for many years to prevent emotional pain and the difficulties of dealing with such terrible experiences.

The American Psychiatric Association claims that many multiple personality disorder sufferers are unable to remember a great deal of information regarding their childhood. It should be noted that not all children who suffer emotional trauma develop personality disorders, but the likelihood of developing any mental health illnesses, especially personality disorders, increases if the trauma is sustained or occurs frequently. In these cases, the child does not have time to recover between periods of abuse, and the dissociative thoughts and feelings can begin to develop into distinct personalities.

The number of distinct personalities varies with each individual case, usually varying from two to 100. The different personalities are known as "alters." Developed alters might closely resemble the original personality or might be completely different, exhibiting entirely unique traits. Differences can include gender, age, mannerisms, dress-sense, vocabulary and even the language spoken. Alters might have different names and are not always human.

Alters also might display biological differences. This differences can include different heart rates, body temperatures, pain thresholds and qualities of eyesight. It also is widely documented that alters might have different reactions to medications, display different allergic reactions and be afflicted with conditions such as asthma in multiple personality patients who do not suffer from any physical health problems.

The core personality, which is the "normal" personality, might remain dominant for many years, with no instances of the alter personalities surfacing. During these periods, a patient might live an ordinary life and be entirely unaware that he or she has multiple personality disorder. When alters do surface, many patients remember nothing of the time spent under the control of an alter. In some cases, the alters are aware of each other and might even communicate with one another.

Multiple personality disorder requires intense and sustained psychotherapy. The average treatment lasts about four years but might last much longer. The therapist must establish a trusting relationship, not only with the core personality but also with each of the alters before he or she can begin to address the trauma-related issues of each separate personality.