I don’t blame you for backing off a movie that focuses on a suicidal teen who learns warm life lessons by spending five days in a Brooklyn hospital’s psych ward. Stop worrying. It’s Kind of a Funny Story, based on Ned Vizzini’s semiautobiographical novel, breaks the jinx. For starters, the writer-directors are Ryan Fleck and Anna Boden, who did Half Nelson and Sugar and rep the best kind of indie cinema, the kind that doesn’t sling bullshit. It helps that Keir Gilchrist, who plays Craig, the teen protagonist, is not some puppy-dog kid actor panting for love. Even if he was, he’d get the piss knocked out of him by Zach Galifianakis, who is terrific as Bobby, a patient-mentor. Galifianakis is a comic force of nature (see The Hangover, as if you haven’t), but he digs down here and delivers a beautifully nuanced performance that gets under your skin. Just like the movie.