The film is an adaptation of Ned Vizzini's 2006 novel of the same name. The book was inspired by Vizzini's own brief hospitalization for depression in November 2004. In 2013, Vizzini committed suicide at the age of 32 by jumping off the roof of the building where his parents lived in Brooklyn.
In the scene where Craig describes other classmates of his, when it shows him you can see he's reading the book 'Be More Chill' by Ned Vizzini, who also wrote "It's Kind of a Funny Story".
On the rooftop Noelle says that she likes the Pixies. Earlier, when she was mad at him and he was outside her door, an instrumental piano version of the Pixies song "Where Is My Mind" is playing.
Shot over a period of six weeks.
In the scene where the patients play instruments, Zach galifianakis pick up the piano. In real life he plays piano during his comedy acts.