 Obsessive-compulsive disorder OCD is a common, chronic, and oftentimes disabling disorder. The only established first-line treatments for OCD are a specific form of Cognitive Behavioral Therapy CBT and the Serotonin Reuptake Inhibitors SRIs. Few patients with OCD experience complete symptom resolution with either modality. Even after two consecutive adequate SRI trials, as many as 30-40 of patients fail to derive a satisfactory response. Pharmacological options for these SRI-resistant cases include switching to a different antidepressant, increasing the dose of SRI, or augmentation with another agent. 