Neurobiology of Sensory Phenomena in Obsessive-Compulsive Disorder

The Research Domain Criteria (RDoC) approach seeks to address the neurobiological mechanisms of sensory symptoms in patients with obsessive-compulsive disorder (OCD) by investigating dimensional components of behavior that more closely align with brain circuitry. This project focuses on the dimensional symptom of sensory phenomena (SP), which are uncomfortable or aversive sensory experiences that drive repetitive behaviors in OCD, including "not just right" sensations, physical urges, and sensations of disgust. SP are very prevalent, occurring in 60-80% of OCD patients, and experienced as highly distressing. Unfortunately, SP are not well addressed by standard treatment approaches, which may be in part because their neurobiological mechanisms are not well understood. This project builds on our preliminary data to (1) investigate the neural mechanisms of SP in large OCD cohort showing the full range of SP severity and (2) probe for familial risk markers in unaffected siblings of patients. For Aim 1, SP will be measured in 100 OCD patients using the Sensory Phenomena Scale. Diffusion and fMRI data will be acquired during rest and fMRI tasks. In order to identify familial risk markers, Aim 2 will compare sensory phenomena and neural circuitry between OCD probands, 50 unaffected biological siblings of OCD patients, and 50 unrelated healthy controls without a family history of Axis 1 disorders.