REASONS: Schizophrenia is typically an adult neurodevelopmental disorder that has its antecedents in childhood and adolescence. Little is known about disorders "usually first diagnosed in infancy, childhood and adolescence" (e.g., childhood-onset disorders) in "prodromal" teens at heightened clinical risk for psychotic disorder. MAIN FINDINGS: Childhood-onset disorders were prevalent in putatively prodromal teens, including anxiety and disruptive disorders, attention-deficit/hyperactivity disorder (ADHD), and, surprisingly, elimination disorders. These may reflect developmental antecedents in psychotic disorders such as schizophrenia. KEY DATA AND STATISTICS: A case series of 9 teens (ages 13-17) identified as prodromal to psychosis were evaluated with the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). Childhood-onset diagnoses commonly endorsed (threshold or subthreshold) included ADHD (5/9), oppositional defiant disorder (5/9), enuresis or encopresis (4/9), conduct disorder (2/9), separation anxiety (3/9), and transient tic disorder (2/9). Enuresis was identified in 3 of the 4 older teens (ages 15-17). MAJOR CONCLUSIONS: An understanding of the childhood-onset disorders that occur in teens at risk for psychotic illnesses, such as schizophrenia, can shed light on the pathophysiology of schizophrenia and potentially inform early identification and intervention.