The primary focus of my research has been developing psychological treatments for children who engage in extreme aggressive and antisocial behavior. Such behaviors are relatively prevalent (approximately 9–10 percent of children in the United States) and are among the most frequent bases for referring children to treatment (up to 33 percent of cases of children seen in treatment). The behaviors occur in both boys and girls but are much more prevalent among boys. In the long term, children with aggressive and antisocial behaviors are at greatly increased risk for mental health problems (eg, psychiatric disorders, substance abuse), physical health problems (eg, early death from disease), and criminal behavior (eg, domestic violence, child abuse). The problem of aggressive and antisocial behavior is very costly for society because the children require many social and hospital services, are often taken to emergency rooms for behaviors that are dangerous or uncontrollable, are in special classes at school, and are in repeated contact with the criminal justice system. Until recently, no interventions had been shown to have impact on the problem–not medication, psychotherapy, special experiences (eg, wilderness camps), or special diet.