A seven-year-old girl has begun refusing to go to school, clinging to her mother each morning, crying inconsolably, saying her stomach hurts. The pediatrician finds nothing physically wrong. The school suggests behavioral problems. The parents wonder whether this is normal childhood difficulty or something that needs intervention, and if intervention, what kind and where to find it. An eleven-year-old boy has been having angry outbursts that seem to come from nowhere, destroying things in his room, screaming at his parents, then crying in confusion afterward.