The movie trailer starts by saying (not exact words): "In 1969 some went to Vietnam, some went to Woodstock, and others went to Claymore (the mental hospital in the movie)." Well in the movie Susanna is supposed to have gone to the hospital shortly after her high school graduation. If you notice the banner when Susanna flashes back to her graduation, it says 1967. I also read the book and the real Susanna went to the hospital in 1967. So, the movie trailer jumps ahead 2 years from the actual movie.