Movie in an insane asylum

[Jack]

This came out in maybe the late '90s or early 2000s.  A young doctor goes to work in an insane asylum and meets an attractive young nurse.  Strange things are happening at the asylum, and the doctor meets a patient who's kept in an isolated room.  The guy hides in the shadows.  This patient seems to know all the secrets of what's going on.

SPOILERS!!!

In the end, the doctor realizes there is no man in the room, and the doctor is the one that's insane.  He goes on a bit of a rampage, killing the young nurse. 

I've been meaning to pick this up on DVD forever, so long in fact that now I've completely forgotten the name of it!   

[Puzzled]

To clarify, is the doctor who goes insane the main character, or another doctor? Or in other words is the doctor who realizes there's nobody in the room the one who's insane?

[Fausto]

It sounds like Madhouse, with Lance Hendrickson, Joshua Leonard (the guy from the blair witch project) and Jordan Ladd. Pretty good stuff.

http://www.imdb.com/title/tt0363276/

In this case, if I remember correctly, the young doctor discovers that he himself is insane.

[Jack]

Yup, that's it, Madhouse.  Thanks!  It's a pretty good film, the ending took me totally by surprise.