"It’s often a haunted house attraction dressed up with some kind of mental illness theme..."

This article on MSNBC explores the prevalance of psycho-killers - and other mentally ill persons - in the horror film genre. It mentions the National Alliance on Mental Illness, and the program StigmaBusters. The article also mentions one of my favorite "haunts" as an adolescent - Paramount's Kings Island.

This article in the Chicago Tribune has more about this very topic.