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

The goal of this clinical trial is to evaluate the efficacy and influencing factors of the combination of the anterior limb of internal capsule and nucleus accumbens (ALIC-NAc) deep brain stimulation (DBS) in patients with treatment-refractory obsessive-compulsive disorder (OCD). The main questions it aims to answer is: Does the timing of DBS activation (at 1, 2, or 3 months post-surgery) affect the reduction rate in Y-BOCS scores? Researchers will compare three groups-DBS activated at 1, 2, and 3 months post-surgery-to determine whether earlier or later stimulation leads to greater symptom improvement. Participants will: * Undergo surgical implantation of an intracranial neurostimulation system targeting ALIC-NAc * Be randomly assigned to one of three DBS activation timing groups * Receive regular clinical assessments over a 6-month follow-up period after activation