More than 90 percent of adults with current substance use disorders started using before age 18, engaging in behaviors that affect healthy neurological and psychological development. This handbook provides a comprehensive, up-to-date overview of the nature and extent of substance use by children and adolescents. Discussion is included on the direct impact on health, safety, and well being, as well as that of families and communities. This book will enable mental health professionals, students, and policy makers to develop effective prevention and treatment services for children and adolescents affected by substance abuse.