multiple personality disorder (MPD), is a mental disorder characterized by the maintenance of at least two distinct and relatively enduring personality states.
Multiple personality disorder (MPD) — The former, though often still used, term for dissociative identity disorder (DID). Primary personality — The core personality of an DID patient. Trauma — A disastrous or life-threatening event that can cause severe emotional distress.
They include antisocial personality disorder, borderline personality disorder, histrionic personality disorder and narcissistic personality disorder.
MULTIPLE SYMPTOMS RATHER THAN 'MULTIPLE PERSONALITIES'
In practice, the vast majority of people with dissociative identity disorder do not obviously present as if they have 'multiple personalities'. ... But many symptoms may appear to be non-trauma-related, such as depression, substance abuse, eating disorders and anxiety.