Dissociative Identity Disorder (DID), also known as Multiple Personality disorder is basically a mental disorder. The person suffering from DID tends to show at least two different types of personality states. Psychiatrist Paulette Gillig coined the term <em>Ego</em> state referring to the normal personality state of a person and "<em>Alter Ego</em>" state referring to the other personality state of the person. Multiple personalities occur alternatively. During one personality state the person has no memory of the other personality state.
