I didn't really feel "horror" or "fright" in this movie. In fact I didn't feel much of anything because it was obvious the entire time what was happening. It wasn't like there was any chance of Dennis Quaid being crazy/insane.
This movie didn't have much plot in my eyes, and was extremly slow. I only enjoyed the performances, but besides that even some of the chracters felt tacked on, like they had no purpose.
Also, the ending absolutly annoyed me, and made no sense.
Please don't watch this movie, it kept my attention less that the fly that was on the edge of my TV screen. When the fly flew away, my eyes followed the fly, not what was happening on the TV. I beg you not to watch, unless you want to be bored and see good actors ruin their good acting reputation.