Vera Farmiga gives a stunning performance as a working-class woman in upstate New York whose coke addiction is destroying her relationship with her two young sons. After going into rehab she meets a wise male nurse (Hugh Dillon), a former addict, and his loving support stands in stark contrast to her husband’s continuing drug use. Writer-director Debra Granik began this as a documentary project about a real-life family but eventually turned it into a drama, and the relatively conventional addiction plot is enhanced by a sure sense of place, class, and family rhythm. 105 min. Gene Siskel Film Center.