A death in the family is always devastating, even if extreme old age or terminal illness is the cause. But the shock of bereavement is infinitely greater when a teenage family member commits suicide. Relatives are left to cope as best they can with feelings of grief and guilt. Once unusual, teenage suicide has become increasingly common in recent decades. Suicide now ranks as the third leading cause of death among people ages 15 to 24. Programs designed to identify and help at-risk youths have proliferated nationwide. Though no one challenges the goal of dissuading young people from taking their lives, experts disagree on whether prevention programs should include all teenagers or only those thought to be at greatest risk.