Michael Douglas has looked back on his role as producer of 1975's Oscar-winning classic One Flew Over the Cuckoo's Nest - which included a film crew made up of the "criminally insane".
The 72-year-old legendary actor - who, along with co-producer Saul Zaentz, won a Best Picture Academy Award for the drama adapted from Ken Kesey's novel - revealed he initially had doubts about casting Jack Nicholson in the lead role of charismatic criminal R.P. McMurphy.
"Hal Ashby, who had been in the early running for director, suggested Jack Nicholson for McMurphy," Douglas told The Guardian. "It was difficult to see at first, because he'd never played anyone like that before.
"We were delayed for about six months because of Jack's schedule, but that turned out to be a great blessing: it gave us the chance to get the ensemble right.
The first actor Douglas did cast was Danny Devito as fellow inpatient Martini. Danny and Devito were close friends and had been roommates in the late 1960s, and Devito had previously played the role in an 1971 off-Broadway production.
The casting of Chief Bromden (Will Sampson) was a little bit less conventional, as Douglas recalled: "I found Will Sampson, who played Chief Bromden, through a used car dealer from Oregon who I'd sat next to on a plane.
"It turned out his dad was a Native American agent and he sold a lot of cars to them. I said we were looking for a big guy to play the chief and, six months later, got a call: 'Michael, the biggest sonofabitch Indian came in the other day!'"
Douglas also admitted that he and Zaentz made the "insane decision to shoot the film in an actual mental hospital in Oregon in January, when it gets dark at three in the afternoon."
He divulged that the hospital's director, Dean Brooks - who ended up playing Nicholson's supervisor in the film - "wanted to incorporate his patients into the crew", and that it wasn't until later on that they discovered "an arsonist" had worked in the art department.
"We ended up with a number of them working in different departments," Douglas went on. "I didn't realise until later that many of them were criminally insane. We had an arsonist working in the art department.
"Dean identified a patient for each of the actors to shadow and some of the cast even slept on the wards at night."
Douglas's father, screen icon Kirk Douglas, had originally acquired the rights to Kesey's novel, but Douglas regrettably fell out with the novelist as he struggled to adapt it into a screenplay.
"Like a lot of novelists trying to adapt their own material, it didn't work out," he explained. "We fell out with him after that. It was our only longstanding, painful issue. We got in to a financial dispute - it was silly, but maybe it was his way of defending his ego."
And on the impact the film had on attitudes surrounding mental health in the mid '70s, Douglas added: "A lot more mentally ill people started coming out of the closet after that.
"The film allowed them to be seen as human beings."
One Flew Over the Cuckoo's Nest won five Oscars, including Best Picture, Best Actor for Jack Nicholson, Best Supporting Actress for Louise Fletcher as Nurse Ratched, Best Director for Milos Forman, and Best Writing for Lawrence Hauben and Bo Goldman.