Dissociative Identity Disorder

Dissociative Identity Disorder (previously known as multiple personality disorder), is a controversial diagnosis of a psychological disorder that manifests itself in the presence of two or more alternate personalities in the same body that may or may not be aware of each other's existence. It is believed to be the result of severe childhood trauma. Several popular books and movies (The 3 Faces of Eve and Sybil, amongst others) have been based on this diagnosis.