Adolescent behavior disorders are mental disorders (significant cognitive, emotional, behavioral, and/or physiological impairments) that either first present during adolescence (ages 13 to 18) or are prevalent within this age group. Common adolescent behavioral disorders include anxiety disorders, mood disorders, disruptive disorders, eating disorders, and psychotic disorders. Because adolescents are undergoing significant physical, cognitive, social, and emotional changes, the presentation of disorders and their subsequent treatment can differ considerably from similar disorders in children and adults. This entry provides an overview of the common behavioral disorders in adolescence; general guidelines for assessment and diagnosis; treatment strategies; and [Page 24]other considerations for health professionals and practitioners who work with affected adolescents, families, and schools.