Justin Cobb's father has a problem. His teenager still relies on the safety blanket that is sucking his thumb. That's only the catalyst in this film that is one part family issues drama, one part coming-of-age, tongue-in-cheek comedy.
What separates Thumbsucker from its contemporaries is its atypical sense of humility. We interpret the conflicts based on the dialog, and therefore understand based on our own moral set. Mills does not ask us to move right or move left in situations concerning topics like drug use (both medical and illegal) and underage drinking. He presents the events and allows us to come to our own conclusions. Unlike other films that exhibit humility such as Pleasantville with its intentionally flaky in its first half that it utilizes to drive its point home that much harder, 'Sucker simply presents the spoon and invites us to decide if we want to eat or not. With the Polyphonic Spree doing the soundtrack, it's at least worth a rental.