Mental disorders in children are quite common, occurring in about one-quarter of this age group in any given year. The most common kind of mental disorders are anxiety disorders, like generalized anxiety disorder and separation anxiety disorder, behavior disorders like attention deficit hyperactivity disorder (ADHD), mood disorders like depression, and substance-use disorders like alcohol use disorders.
ADHD affects 8%-10% of school-aged children. Depression occurs at a rate of about 2% during childhood and from 4%-7% during adolescence, affecting up to about 20% of adolescents by the time they reach adulthood. In teens more frequently than in younger children, addictions, eating disorders, bipolar disorder, and less often early onset schizophrenia may manifest. Autism occurs in one out of every 59 children.