Dissociative identity disorder, previously called multiple personality disorder, is usually a reaction to trauma as a way to help a person avoid bad memories.

Dissociative identity disorder is characterized by the presence of two or more distinct personality identities. Each may have a unique name, personal history, and characteristics.

Sorry to say that's not me or never has been because to have multiple personalities you are in a world of your own where you attend to talk to yourself and answer yourself back and where you hear the voices of the other personalities talking back to you telling you to do this or that which me,myself and I don't or never have done that but I have been a witness to someone like that and it's scary needless to say but all you can do is get that person medical help before they hurt themselves or someone else