Dissociative identity disorder (DID), previously known as multiple personality disorder (MPD), is a mental disorder characterized by the maintenance of at least two distinct and relatively enduring personality states. The disorder is accompanied by memory gaps beyond what would be explained by ordinary forgetfulness. The personality states alternately show in a person's behavior; however, presentations of the disorder vary. Other conditions that often occur in people with DID include post-traumatic stress disorder, personality disorders (especially borderline and avoidant), depression, substance use disorders, conversion disorder, somatic symptom disorder, eating disorders, obsessive–compulsive disorder, and sleep disorders. Self-harm, non-epileptic seizures, flashbacks with amnesia for content of flashbacks, anxiety disorders, and suicidality are also common.
