The multiple personalities form the source of the disorder's original name, "Multiple Personality Disorder"; it was changed because the new name provides a better explanation of motivation. Note that without receiving psychological counseling, the symptoms will carry over into adulthood. The individual has no control at least initially over when the personalities "switch" and may not initially remember what happens to him while they are switched. To put all that in Tropese: you go to your Happy Place while some poor Red Shirt has to deal with the Trauma Conga Line or Humiliation Conga — so stereotypically, the personality who has to deal with it is not a nice person
victorian era – Dissociative Identity/Multiple Personality
Affected individuals may be unable to form intimate attachments to others and simultaneously possess a rich and elaborate but exclusively internal fantasy world. The cause of SPD is uncertain, but there is some evidence of links and shared genetic risk between SPD, other cluster A personality disorders such as schizotypal personality disorder and schizophrenia. Thus, SPD is considered to be a "schizophrenia-like personality disorder". The effectiveness of psychotherapeutic and pharmacological treatments for the disorder has yet to be empirically and systematically investigated. This is largely because people with SPD rarely seek treatment for their condition. SPD is a poorly studied disorder, and there is little clinical data on SPD because it is rarely encountered in clinical settings. People with SPD are often aloof, cold and indifferent, which causes interpersonal difficulty.
Split personality disorder: Signs, symptoms, causes, diagnosis, and more
Dissociative Identity Disorder. Movies Dissociative Identity Disorder. Half these movies are based on the real lives of people with multiple personalities, the others entirely are fictional.
Borderline personality disorder BPD , also known as emotionally unstable personality disorder EUPD ,  is a mental illness characterized by a long-term pattern of unstable relationships , distorted sense of self , and strong emotional reactions. The causes of BPD are unclear but seem to involve genetic, neurological, environmental, and social factors. About 1.