This film was based on the writings of James Fogle, who was a real-life criminal and drug addict who robbed drugstores.
William S. Burroughs' part was originally just as Tom the junkie. He agreed to do the part as long as he could write more of a story to the character. He rewrote the back story and the dialogue himself.
Around the thirty-minute mark, Bob accidentally smashes the lamp behind him while swinging his golf club. This was not actually scripted; it was a real accident by Matt Dillon.