The director, writers, and producers of One Flew Over the Cuckoo’s Nest faced a formidable challenge in adapting Ken Kesey’s novel into a story that would work on the screen. Kesey wrote the novel while working as an orderly in a psychiatric ward and while participating in psychology-department experiments with LSD, mescaline, and other chemicals in order to earn extra money while attending graduate school at Stanford. He began to have hallucinations of a large Native American man sweeping the floors. The Chief became the narrator of his novel, and all the events of the story were told through his eyes. Like Kesey, the character of the Chief suffered from hallucinations: he held a firm belief that Nurse Ratched worked for an evil Combine that twisted and manufactured men. The novel became very popular with the counterculture movement after it was published in 1962, and its paranoia suited the antiwar activism of the era.

Because a film is a very different storytelling medium from a novel, Forman knew that Kesey’s story had to be changed to fit the new format, as well as updated to be relevant twelve years later. Equally problematic was the fact that psychedelic illusions of humans changing form or walls sprouting arms would not translate well to the screen, nor would the mythical Combine suit Forman’s interest in cinematic realism. The Broadway play of 1963 retained these features of the novel by having the Chief slip to the front of the stage to address the audience in asides, but this approach would look stilted on film.

To adapt the story so that it would work as a motion picture, the filmmakers changed the point of view to an omniscient, all-seeing perspective. The camera focuses upon the characters directly rather than interpreting them through the Chief’s eyes. This choice eliminated the need for both the hallucinations and the conspiracy of the Combine. Rather than being controlled by an evil machine, in the film adaptation Nurse Ratched is the ultimate authority-wielding bureaucrat. Forman understood that audiences would better relate to the struggle against a personified, rather than mechanical, enemy. His Nurse Ratched relies upon rules and her power to change them arbitrarily in order to enforce conformity over individualism.

Although Forman elected to retain many of the novel’s references to McMurphy as a Christ figure, he chose a more subtle approach for the film. For example, his electric shock table is not in the form of a cross, and McMurphy does not ask whether he gets a crown of thorns, as he does in the novel. The ending of the film, as of the novel, deals with death and resurrection. However, Forman modifies it for the screen: in the novel, by the time McMurphy returns from his lobotomy, most of the patients on the ward have already signed themselves out and managed to escape before McMurphy and the Chief do. In the film, all the characters are still on the ward. Forman’s Chief escapes alone, leaving the window gaping open behind him for those who might choose to follow—a visually satisfying image that also underscores the importance of independent thought to a joyful life.