Dissociative identity disorder, once called multiple personality disorder, is the subject of this 1993 HBO documentary from producer-director Michael Mierendorf. The film opens with a genuinely rare piece of archival footage: a 1920s research film showing a woman whose distinct personalities emerge on camera, including a male alter uncomfortable in women's clothing and a personality that behaves as a young child. Mierendorf traces the diagnosis back through medical history, from earlier explanations involving spirit possession to nineteenth-century studies of hysteria that first proposed a single person could host separate, independently functioning identities. Interviews and case material connect the condition to its clinical present, showing how a phenomenon once treated as supernatural affliction became a recognized psychiatric category. The old footage is the film's strongest asset, giving viewers a direct look at behavior that later decades would only describe secondhand. It is a short, focused history of one diagnosis rather than a survey of trauma or memory in general.