This 3-year school-based epidemiological study on child and adolescent mental disorders aims to obtain the prevalence rate and identify the psychosocial, individual, environmental, and familial risk factors for mental disorders including learning disability, autism spectrum disorder, attention-deficit hyperactivity disorder, oppositional defiant disorder, conduct disorder, mood disorders (major depression, dysthymia, bipolar disorder), anxiety disorders, phobia, obsessive compulsive disorder, sleep disorders, eating disorders, and substance use disorders in Taiwan.