Factual error: When Mike first starts listening to the session tapes, the camera does a slow pan down the label on the box. Quite clearly, we can see that the patient's diagnosis is listed as "D.I.D.", along with a few names. Since the hospital closed in the mid 80's, it is not possible for her to have that diagnosis. Before the early 1990's, D.I.D. (Dissociative Identity Disorder) was known as M.P.D. (Multiple Personality Disorder). In later scenes it is correctly listed in the woman's files as Multiple Personality.
Session 9 (2001)
1 factual error - chronological order
Directed by: Brad Anderson
Starring: Josh Lucas, David Caruso, Paul Guilfoyle, Stephen Gevedon
Continuity mistake: Gordon mentions that his wife accidentally spilled hot water on his leg and burnt it, but the actor only occasionally limps on it, although we are shown that he has an injured leg. This is mentioned on the commentary.
Trivia: The movie was filmed on Sony High Definition camcorders as opposed to traditional 16 or 35mm film. The camcorders used were among the first to offer the cinema standard 24 frames-per-second as an option (as compared to the home-video standard of 30fps) which helped make the image look closer to cinema-quality. The movie was one of the first mainstream films shot primarily on digital video.