Judith Anderson wrote:
Louise Fletcher also won best actress, Jack Nicholson best actor and the film won best picture and other awards. It was based on a book that was published in 1962, so more than likely it was set in the same period, i.e. the 50s that Shutter Island was. Or perhaps even before then. But lets say it was set in the Fifties. It was based on reality back then, but the Scientologists who gloated over the "Evil SPs" in the movie were not in the "reality zone." They were not in the 50s, they were still in 1975, in freeze frame mode. Their perception of psychiatry had not changed and still has not to this day.
The novel, written by Ken Kesey, was based on time he spent in the 1960's at the VA hospital in Menlo Park. My father worked at that VA hospital during that time, and said he had a pretty good idea on who Nurse Ratched was based. She was apparently a pretty cruel person. Things have definitely changed quite a bit from the 50's and 60's, with the advancement of more humane and effective treatment of seriously disturbed people.