Session 9 (2001) is one of my favorite movies.
It's not faced-paced, but it is sufficiently creepy to keep the viewer interested.
The movie takes place at an abandoned mental hospital where the characters are a team of guys that do asbestos clean-up. One fella slacks off the job and finds some old reel-to-reel recordings of a psychiatrist and a patient discussing the patient's multiple personalities. The patient is a little girl.
Anyway...I highly recommend this movie!!
By the way, if you have acces to starz movie channels (I have Directv), it is on encore on the 5th and 6th of Sept and on the mystery channel on the 24th of Sept.
SPOILER: supernatural?