The purpose of this clinical study is To verify the long term effectiveness and safety of a bilateral deep brain stimulation (DBS) produced by Beijing PINS Medical Co., Ltd. as a treatment option for patients with cognitive, behavioral, and functional disability of Obsessive-Compulsive Disorder.

Inclusion Criteria:

1. Obsessive compulsive disorder (according to DSM IV-criteria) as the primary psychiatric diagnosis.
2. Severity level of OCD more than 25 on the Yale-Brown Obsessive Compulsive Scale.
3. Course of illness had to have been present for at least five years in a chronic or progressive form despite any treatment trials (treatment resistance).
4. Treatment resistance: at least two serotonin reuptake inhibitors (SSRI´s), or one SSRI and clomipramine in 5.Sufficient dosages for at least 10 weeks, an augmentation trial with lithium, buspirone or a neuroleptic Lasting at least 10 weeks, and complete cognitive-behavioral psychotherapy, including "exposure and response Prevention" of a minimum of 20 sessions with a documented lack of efficiency.

6.The ability to give written and informed consent.

Exclusion Criteria:

1. Co-morbid psychotic disorder according to DSM-IV criteria
2. Suicidal tendencies in the last 6 months
3. History of cerebral trauma
4. Clinically relevant internal or neurological disorder
5. Substance misuse or dependence in the last six months
6. Ineligibility to fulfill the neurosurgical and anesthesiological preconditions for the implantation of a DBS
7. Participate in other clinical trial
8. The investigator and/or enrollment review committee, would preclude participation in the study