I definitely have elaborate fantasies involving mental institutions, although it is not something I would be able to enact in real life. Like other people who have posted I have had experience with psychiatric wards, but I enjoyed absolutely nothing about them. The places I was in were comfortable and nice looking, the staff all maintained professional demeanors, and the treatments were limited to pills and therapy. Oh, and no strip searches or forced exams of any kind. My main memory is of feeling horrible (which was why I was there in the first place), and I plan on never going back.
HOWEVER, many of the more traumatic aspects of being hospitalized have worked their way into my fantasies (standard eroticization of intense negative experiences, I guess) in greatly exaggerated form. Lack of control, lack of privacy, submitting to 'treatments' you do not understand, fear of punishment/actual punishment, being told that unpleasant treatments are actually 'good for you,' no one listening to what you want...you get the idea. All those themes are pretty easily translated from purely psychological experiences into physical ones that are both sexual and painful. I could go on for a long, long time but that is for the fantasies, dreams board.
So I guess what I'm saying is for me, real experience-sucked, my way of coping with it-very hot fantasy material.
As a side note, there's an awesome story in the new submissions section that involves this theme:
http://www.zity.biz/index.php?mx=forum;ox=display;topic=22083.0