Identifying Local Field Potential Biomarkers for Obsessive-compulsive Disorder Treatment With Deep Brain Stimulation

Inclusion Criteria: 1. Diagnosed with OCD according to the criteria in the DSM-5. 2. Age between 18 and 65 years. 3. Duration of illness of more than 3 years. 4. Ineffectiveness of systematic treatment with three types of serotonin reuptake inhibitors (including clomipramine) and augmentation agents, with no improvement after continuous high-dose serotonin reuptake inhibitor treatment for more than 12 weeks, or the occurrence of severe adverse drug reactions during treatment. 5. Ineffectiveness of CBT treatment or repeated refusal of CBT treatment. 6. Y-BOCS total score of 25 or higher. 7. Significant impairment in social functioning, such as inability to work or attend school, or a noticeable decline in personal life skills. 8. No severe impairment in insight, and capable of signing informed consent and surgery consent forms. Exclusion Criteria: 1. Presence of bipolar disorder, schizoaffective disorder, schizophrenia, or other psychotic disorders. 2. Severe personality disorders. 3. Severe physical illnesses or organic brain diseases. 4. Diagnosis of alcohol or substance abuse and dependence according to DSM-IV criteria within one year prior to screening. 5. Study participants with contraindications for surgery, such as major medical comorbidities or inability to discontinue anticoagulant medications. 6. Preoperative head MRI showing significant structural abnormalities. 7. Contraindications for MRI examination (excluding the DBS implant or stimulator itself). 8. Pregnancy or breastfeeding. 9. Study participants currently enrolled in another research study unrelated to the current study. 10. Any condition that currently or in the future might endanger the safety of the study participant or prevent the successful participation in the study (including family support, medical, psychological, social, or geographical factors).