***You can thank Jerry Rivers for getting this ball rolling in the 70s with Willow Brook.****
I think it my have began back in 1967 with a little film named TITICUT FOLLIES.
I believe you are correct.
Titicut Follies! I’ve been trying to think of the name of that movie for ages. Made by the great documentarian Frederick Wiseman who also made High School and the beautiful movie Blind.