My friend's brother worked as a psychiatric nurse and has all kinds of interesting stories about the patients:
One young man thought that Arnold Schwarzenegger was his dad and that all his film roles were real and that he was coming to take him away to the Mars base in Total Recall.
Another could do really accurate impressions and wound all the staff up by mimicing their voices all day, didn't actually ever speak in his own voice.
A compulsive masturbator who would just whip it out anywhere as if nobody was watching, totally oblivious. Got transferred after he started in front of visitors to the ward, including some children. (This is quite common, apparently.)
Sixteen year old lad convinced his entire life was virtual reality. Actually came up with some good philosophical arguments as to why this was the case. My mate's brother found him really interesting to talk to, and was sort of sorry when he recovered.