To contrast the degree and durability of improvement in pediatric obsessive-compulsive disorder (OCD), patients will be treated with 1 of 6 conditions (3 active treatments and 3 control treatments): sertraline alone (SER), OCD-specific Cognitive Behavior Therapy (CBT), both SER and CBT (SER plus CBT), pill placebo (PBO), pill PBO plus Educational Support (ES), and SER plus ES.