The Yale OCD Research Clinic is dedicated to advancing our understanding of the brain changes that contribute to OCD, and to the application of this knowledge for the development of new treatments. Obsessive-compulsive disorder (OCD) is a common and frequently debilitating psychiatric disorder that often goes undiagnosed and undertreated. The Yale OCD Research Clinic has a 25-year history of advances in the neurobiological understanding and treatment of this condition. Our current work, funded by the National Institute of Health, the Doris Duke Charitable Foundation, and other groups, continues this tradition, as we seek to better understand the brain processes that have gone awry in OCD and to use this knowledge to develop new treatments.