Original sentence: Prior to DSM IV it was called multiple personality disorder (MPD).The existance of multiple personalities within individual is categorised as Dissociative identity disorder (DID) in the Diagnostic and Statistical Manual of Mental Disorders (DSM)
Edited sentence: Formerly named multiple personality disorder (MPD), Dissociative identity disorder (DID) is the American Psychiatric Association's current name for this mental disorder in its Diagnostic and Statistical Manual of Mental Disorders (DSM).Significantly, this change was from personality disorder to dissociative disorder