4. Dissociative Identity Disorder
Before the 19th century, people exhibiting symptoms of the disorder were believed to be possessed. An intense interest in spiritualism, parapsychology, and hypnosis continued throughout the 19th and early 20th centuries and may be even till today.
Dissociative identity disorder (DID) is a psychiatric diagnosis that describes a condition in which a person displays multiple distinct identities or personalities (known as alter egos or alters), each with its own pattern of perceiving and interacting with the environment. the name for this diagnosis is multiple personality disorder. Tthe diagnosis requires that at least two personalities routinely take control of the individual’s behavior with an associated memory loss that goes beyond normal forgetfulness.