Dissociative disorders
Dissociative disorders occur when the brain is trying to put some kind of distance between the self and traumatic feelings or experiences. This is a form of defense mechanism which helps people deal with and survive traumatic experiences of the past. The most common form of dissociative disorder is amnesia and, more rarely, multiple personalities.
Since there is no effective proven medication for this disorder, drug treatment is solely designed to alleviate some symptoms, such as amnesia, while therapy is mainly through psychotherapy.