Dissociative identity disorder
Dissociative identity disorder (DID), previously known as multiple personality disorder (MPD), is a mental illness characterized by at least two distinct and relatively enduring personality states. This is accompanied by memory gaps beyond what would be explained by ordinary forgetfulness. The personalities alternately show in a person's behavior; presentations, however, are variable. Other problems which often occur in people with DID include borderline personality disorder (BPD), posttraumatic stress disorder (PTSD), depression, substance use disorders, self-harm, or anxiety.Some professionals believe the cause to be childhood trauma.