Dissociative identity
Dissociative identity disorder is when a person has two or more distinct personalities or identities. Their alternative personalities may be a different age and gender and demonstrate different moods and preferences. When a personality is not in control, it detaches and may be unaware of what is happening. For the question given above, the court-appointed psychiatrist knows immediately that Ferris does not suffer from dissociative identity disorder, as the host is never conscious of the alter egos.