Precision Brain Mapping to Predict and Track Response to Exposure and Response Prevention Therapy in Youth With Obsessive-Compulsive Disorder

The goal of this clinical trial is to learn whether brain scan results can help predict and track changes in obsessive-compulsive disorder, or OCD, symptoms in children and teens ages 10 to 17 who receive Exposure and Response Prevention therapy, also called ERP. ERP is a type of therapy in which participants practice facing OCD-related fears while resisting rituals or compulsions. The main question this study aims to answer is: Can each participant's pattern of brain connections, measured with functional MRI brain scans, help predict and track weekly changes in OCD symptoms during and after a 14-week course of ERP, including during planned monthly booster sessions and additional booster sessions offered if symptoms worsen? All participants will receive ERP. There is no placebo and no comparison group. Participants will: * Complete screening, consent or assent, interviews, questionnaires, and MRI safety checks * Receive 14 weekly ERP sessions * Complete OCD symptom assessments and functional MRI brain scans before, during, and after ERP * Receive planned monthly ERP booster sessions after the 14 weekly sessions * Receive additional brief ERP booster sessions if OCD symptoms worsen during follow-up * Take part for up to about 62 weeks