1994. 109 minutes. New Zealand. Directed by Peter Jackson.
One Flew Over the Cuckoo's Nest
1975. 133 minutes. USA. Directed by Milos Forman
PS - I mentioned movies about madness that glide between hilarious and unsettling and both of these movies do that to one extent or another, but others that fit into this subsubgenre include the quintessential example of American Psycho along with Perfume: The Story of a Murderer and A Scanner Darkly.