The book Jesse discusses with Dean in the coffee house and hospital is David Foster Wallace's "Infinite Jest". Wallace committed suicide in 2008. Dean's situation also resembles the college experiences of Wallace, who was hospitalized for depression while trying to complete his senior thesis, a novel, at Amherst College.
Although not mentioned by name, the "vampire book" that sparks an argument between the two main characters is based on "Twilight". Elizabeth Reaser, who plays Ana in this film, also plays Esme Cullen in the "Twilight" movies. In the film, the book's title is "Lunar Moon". Its cover is similar to that of "Twilight".
There was a storyline with Michael Weston as Miles, a friend of Jesse who is trying to go to Spain but has several issues that keep him from going. All of his scenes were filmed but not in the movie; they are featured in the Bonus section as Deleted Scenes.
In the film's opening Radnor's character is reading God of Small Things, whose plot also deals with the 'laws of love', and what happens to those who break these rules - paralleling the characters of the film.