'Ben is Back' is compelling at first but falls apart

Julia Roberts works well with actor Lucas Hedges, who knows how to be volatile without chewing the scenery.

For its first hour or so, “Ben is Back,” starring Julia Roberts, is a compelling and intelligent study of how drug addiction affects a family. Lucas Hedges plays Ben, who has signed himself out of rehab to be with his mother (Roberts), stepfather (Courtney B. Vance), and siblings for Christmas. His reappearance, unannounced and unauthorized, is not welcomed; despite his protestations to the contrary, they fear he will relapse at any moment.

Roberts, in her “serious” performances, is often a tad too stiff and monochromic, but she works well here with Hedges, who knows how to be volatile without chewing the scenery. They are quite believable as mother and son. (Hedges’s father, Peter Hedges, is the writer-director.) The film falls apart in the end, alas, as the story spins into druggie melodramatics. Grade: B- (Rated R for language throughout and some drug use.)