Based loosely on Susanna Kaysen's 1993 bestseller, James Mangold's Girl, Interrupted is a noble but misguided attempt to turn an episodic, bracingly unsentimental memoir into a fairly conventional coming-of-age story. Set in the late '60s, the film follows the journey of an upper-middle-class teenager (Winona Ryder) placed into an upscale mental hospital following a half-hearted suicide attempt. In adapting Kaysen's book for the big screen, Mangold has stripped away much of its dark humor, replacing it with unbecoming doses of sentimentality and turning a nurse only vaguely sympathetic in the book into a sassy but loving mother figure played by Whoopi Goldberg. By converting Kaysen's tale into a story of female bonding and personal growth, Mangold has sapped the work of much of its understated power and in the process muffled its still-relevant social message: that mental hospitals are often just backward holding pens for society's malcontents. Still, Girl, Interrupted has its rewards. Mangold's films have generally been distinguished by their fine performances, and his latest is no exception. The oft-miscast Ryder is ideally suited to play Kaysen, turning in her best performance in ages as the film's doe-eyed protagonist. But the real standout is a riveting Angelina Jolie as the hospital's charismatic alpha-patient. Her magnetic breakthrough performance has a raw, dangerous, profoundly sad energy that Mangold's equally transcendent and embarrassing film only possesses in fits and starts.