Affecting Real-Life Sanity

[DamnNoHtml]

I've been brainstorming ways to actually make the player start to think he or she is insane without affecting in-game sanity.

The thing is, seeing a Grunt doesn't make you go "insane" it makes you pee your pants, which is completely different. Insanity makes you question what you know.

So far, the only idea I had was creating two identical rooms, except in the second room there is no entrance / exit. When you enter the first room, a script moves you to the parallel position in the other room without the door, so basically the player enters the room and when they turn around, the door they just came in is completely gone.

Any ideas?