Additional Study Information: For this study, eligible participants will be asked questions about their symptoms and complete a medical evaluation. You will receive a medication, and be monitored by medical professionals. You will also be asked to complete questionnaires. The purpose of this study is to assess to evaluate a medication for the treatment of OCD. Specifically, the goal is to learn the difference in how this medication works compared to placebo (or sugar pill with no medication; to evaluate how safe and how well tolerated it is when administered; and to evaluate how it works compared to placebo using scales that assess other aspects of your health that may be affected by OCD. For more information about participating, please call Rachel Middleton at (646) 774-8138 or email her at Rachel.Middleton@nyspi.columbia.edu.