Mistaken identity.

The condition known as Multiple Personality Disorder (MPD) was first diagnosed in the 1950s with the famous case of Sybil who was treated by the psychiatrist Dr Cornelia Wilbur. Wilbur discovered a series of 'alter' egoes which had split off from Sybil's core personality and she attempted to analyse each one. The case led to a book and a movie but there was concern, particularly from psychiatrist Dr Herbert Spiegel, that Wilbur had planted the personalities in Sybil's mind under hypnosis. We meet therapist Sarah Francis who, as well as suffering from MPD herself, treats others with the same condition. She disagrees with Spiegel's claims and has renamed the condition Dissociative Identity Disorder. We hear from friends of Sybil and some of those who treated her as the documentary attempts to piece together the complex life of the first known patient with MPD.