A high-school senior finds that fate (and modern medicine) plays some interesting tricks with his personality in this dramatic comedy. Justin Conn (Lou Taylor Pucci) is a neurotic teenager who has a difficult time with his peers, especially Rebecca (Kelli Garner), a cute girl in his debate class with whom he is somewhat mutually infatuated. It isn't much better at home with his obnoxious younger brother Joel (Chase Offerle), his father, Mike (Vincent D'Onofrio), who is busy having a midlife crisis, and mother Audrey (Tilda Swinton), who's infatuated with one of her favorite TV actors (Benjamin Bratt). All this anxiety has to go somewhere, and Justin's manifestation of his troubles comes in the form of sucking his thumb, which makes him even more of an outcast. Dr. Perry Lyman (Keanu Reeves), an orthodontist who seems to double as a new age therapist, treats Justin with hypnosis; meanwhile, the school psychologist decides he has Attention Deficit Disorder, and treats him with medication. Suddenly, Justin stops sucking his thumb and becomes an outgoing overachiever, single-handedly taking his school debate team to the state championship. But Justin's relationshop with his debate coach, Mr. Geary (Vince Vaughn), becomes strained, and the boy tries to mold yet another new identity for himself. Thumbsucker was the first feature film from Mike Mills, who previously distinguished himself in commercials and music videos.