Efficacy and Influencing Factors of ALIC-NAc Deep Brain Stimulation in Treatment-Refractory Obsessive-Compulsive Disorder

Inclusion Criteria: * aged 18-65 years old; * a diagnosis of OCD based on The Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5); * the Y-BOCS total score ≥ 25; * met the criteria of treatment refractory. Treatment refractory is defined as failed a) Inadequate response or intolerance to at least three adequate trials of selective serotonin reuptake inhibitors (SSRIs), combined with at least two second-generation antipsychotics as augmentation agents. b) Inadequate response or intolerance to cognitive behavioral therapy (CBT) consisting of more than 12 sessions conducted concurrently with adequate dosed SSRIs treatment. Exclusion Criteria: * Presence of other psychiatric disorders such as organic mental disorders, paranoid personality disorder, or mental retardation. * Individuals deemed by the investigator to be at significant risk of suicidal behavior based on clinical assessment. * Presence of severe or unstable cardiovascular, respiratory, hepatic, renal, hematologic, endocrine, neurological, or other systemic diseases. * History of organic brain disorders, traumatic brain injury, intractable epilepsy, or other neurological conditions. * Clinically significant abnormalities in physical examination, laboratory tests, electrocardiogram, or imaging during screening or baseline that, in the investigator's judgment, make the individual unsuitable for the study. * History of implantation of a cochlear implant, cardiac pacemaker, cardiac defibrillator, prior unilateral or bilateral implantation of similar devices, or other surgical procedures within the past six months that may affect study participation as judged by the investigator. * Contraindications to DBS implantation or deemed unfit for surgery by the investigator. * Confirmed HIV-positive status. * Pregnant or breastfeeding women, women of childbearing potential with positive blood/urine HCG results at screening, those unable to use effective contraception during the study, or those planning to conceive within three months after study initiation. * Participation in another drug or medical device clinical trial currently or within three months prior to screening. * Any other condition deemed by the investigator to render the individual unsuitable for the study.