The only aspect of the book I really appreciated was in the end when she looked back and picked apart her diagnoses of "borderline personality" and questioned if there had really been a problem with her beyond those of a fairly normal emotional teenage girl. She clearly feels there is a difference between someone with, say, schizophrenia and someone with issues that can't be as clearly defined such as "borderline personality". I have to say I agree. And from a Christian perspective, I am of the opinion that there are times when chemicals in the brain aren't as they should be and cause problems in the same way skin develops acne, cancer presents itself in various organs, or eyes become nearsighted. On the other hand, some of the conditions that are considered mental problems can also be spiritual. I think it is tricky to maintain a balanced view of mental conditions for many Christians.
I'm not really sure how this book came to be made into a movie. Some books simply scream to become movies; this one did not. If you're interested in the subject of mental hospitals and mental illness, especially in the late 60's, you might enjoy this book. Otherwise, skip to something more interesting.