Low-intensity Ultrasound for Individuals With Obsessive-compulsive Disorder

The goal of this clinical trial is to learn whether low-intensity focused ultrasound (LIFU), a non-invasive form of brain stimulation, can change brain activity and improve thinking and decision-making in adults with obsessive-compulsive disorder (OCD). The main questions it aims to answer are: Can active LIFU change activity in brain pathways involved in OCD? Can active LIFU improve the ability to control thoughts and actions? Researchers will compare active LIFU with sham LIFU to see whether active LIFU causes changes in brain activity and performance on behavioral tasks. Participants will: Complete questionnaires and behavioral tasks. Have magnetic resonance imaging (MRI) scans to measure brain activity and identify the area to receive LIFU. Receive both active and sham LIFU on separate visits. Have MRI scans and complete behavioral tasks after each LIFU session. Complete assessments of OCD symptoms, safety, and possible side effects.