Inclusion Criteria:  Severe OCD according to the Diagnostic and Statistical Manual of Mental Disorders: DSM-IV YBOCS score of at least 25/40 Disease duration of ≥5 years with persistent disabling symptoms despite adequate trials with at least 3 different serotonergic acting antidepressants, augmentation with antipsychotics, and CBT Only patients between 18 and 65 years of age who could understand and comply with instructions and provide their own written consent.  Exclusion Criteria:  Current psychotic or substance abuse disorder Clinically significant medical disorder, or previous brain surgery