It is indeed a true - story - based creation. Ken Kesey got a first - hand look at mental institutions when he worked at one. He was able to observe the different personalities of the patients and the way the staff interacted with them. This led to the creation of a story that showed the struggle between the individual and the conformist, controlling environment of the mental ward. The characters in the story, such as Nurse Ratched, were modeled after the types of people he encountered in real life.
Yes, it is based on a true story. The novel was inspired by Ken Kesey's experiences working in a mental hospital. He witnessed the power dynamics and the dehumanizing treatment in such institutions. For example, the strict control exerted by the nurses over the patients, much like in the story.