as Yakko said before, it would have to be The Wheel.
i couldn't stop thinking about the movie 'Murder in the First' when i read this post. even though he survived it, Henri Young (played by Kevin Bacon) was locked up in totally dark room by himself for something like 2 years straight. he was let outside only once during this period, for 30 minutes, only to be thrown back in the dark cell. there was no toilet, no windows, no light... and he was left there all naked. when he was finally taken out, Henri Young had gone insane. the story was chilling, because it was all based on a true story.