Multiple personality disorder is a type of dissociative disorder in which patients have two or more completely different identity states. More common in females, with a male to female ratio of 1:9
Clinical symptoms are as follows: the patient suddenly loses all memory of his past events, cannot recognize his original identity, and carries out daily activities in another identity. It manifests as two or more obviously different personalities, each with its own memory, hobbies and behavior, completely independent, alternating, and unrelated to each other.