Inclusion Criteria:  Ability to give informed consent for the study Age 22-75 Clinical diagnosis of OCD Documented duration of OCD of at least 5 years OCD rated as severe or extreme illness (YBOCs ≥ 28) Has failed to improve following treatment with at least two selective serotonin reuptake inhibitors (SSRIs), clomipramine, and augmentation with antipsychotics Has not responded to adequate trials of cognitive behavior therapy (exposure and response prevention) Has not responded adequately to TMS treatment for OCD if it is reasonably available to the patient  Exclusion Criteria:  Has hoarding as a primary subclassification of OCD according to DSM-4 Has another severe psychiatric disorder (personality disorder, psychotic/bipolar disorder, etc) or substance abuse issues Is pregnant Has an abnormal MRI assessed by the team or has a neurological condition requiring an MRI in the future Has a cognitive disorder or dementia Is at imminent risk for suicide based upon Suicide Severity Rating Scale (SSRS) or has ever attempted suicide Inability to comply with study follow-up visits Major comorbidity increasing the risk of surgery (prior stroke, severe hypertension, severe diabetes, or need for chronic anticoagulation other than aspirin) Allergies or known hypersensitivity to materials in the Activa systems (i.e. titanium, polyurethane, silicone, polyethermide, stainless steel). Previous cranial ablative or deep brain stimulation surgery. Patients may be excluded from enrollment due to a condition that, in the judgement of the PI, significantly increases risk or reduces significantly the likelihood of benefit from DBS.