As stated previously, the novel by Stephen King relied heavily on Paul Sheldon' s inner workings. The idea of trying to capture this one-sided, internal story on film is an obstacle on it's own. This being said, there were scenes added into the movie that did not take place in the book. The scene in which Paul asks Annie to eat dinner with him so he can try to slip his pain medication into her drink is an example of one on these changes. In the book, Paul thinks of doing this, but decides it is much too risky and could end up with Annie killing him. They added this scene into the film due to the fact that we cannot hear Paul's thoughts. The fact that Paul's plan to overdose her completely fails in the film and has no consequences tells us that this scene was added to show what was going through Paul's mind.
As well as adding or replacing scenes, the film took the liberty of adding or replacing characters. For instance, in the book a young state trooper makes a routine visit to Annie's house. At this point, Paul has been gone for some time but no one is too worried about his disappearance. They assume that Paul must have finished his new book and took a vacation to celebrate. Annie ends up killing the trooper which leads to even more visits by law enforcement. In the film, all of the law enforcement is replaced by a character named Buster. Buster is the town sheriff and seemingly the only real officer for miles. He starts his own one-man investigation into Paul's disappearance, which is an active sub-plot for the majority of the movie. Buster replaces the book's young state trooper along with the two detectives who come looking for the said trooper.
Another charcter the movie completely adds to the story is that of Paul's daughter. She is never shown on screen in any form, but is mentioned several times. King made it a point in the book that Paul was somewhat of a loner, and had been divorced more than once.
Misery the film is widely known as one of the most horrorifying films about an obsessive stalker. Thus it comes as little surprise that the film is more about horror and thrills while the book focuses on Paul's excruitating mental journey. Since the book more closely follows Paul's thoughts and feelings, the reader gets a much more intimate and personal connection with the story. The reader is essentially put in Paul's place and experiences everything with him. The film takes a more passive role, and to a degree the watcher is removed from the story. The movie's toned down horrors makes it much less traumatic for the viewer and for Paul. For example, although it is depicted in both the book and the film, Paul's PTSD after the entire experience is much less severe in the film. In the book, the audience reads as Paul is constantly betrated with terrifying images of Annie long after he has escaped her and she is dead. He sees her everywhere he goes, and is constantly in some state of fear. In the film, this traumatic condition is only depicted once at the end, and Paul seems to have a handle on the situation. He looks the fake Annie in the eye, and delievers the one-liner to close the movie. Overall, the movie is much less personal and alarming for the viewers than the book is for the readers.