The Efficacy and Safety of ALIC/NAcc-DBS for Treatment-refractory OCD

Inclusion Criteria:

• aged 18-65 years old;

• a diagnosis of OCD based on The Diagnostic and Statistical Manual of MentalDisorders, fifth edition (DSM-5);

• suffered from severe OCD symptoms over 5 years with substantial functionalimpairment;

• the Y-BOCS total score ≥ 25;

• met the criteria of treatment refractory. Treatment refractory is defined as failed

1. at least three adequate therapeutic trials of serotin reuptake inhibitors (SRIs),with clomipramine being one of the SRIs trials, 2) the use of at least two atypicalantipsychotics as augmenting agents, 3) at least 20 sessions of therapist-guidedcognitive-behavioral therapy while on a therapeutic dose of an SRIs. These patientshave "failed" treatment by demonstrating <25% reduction of Y-BOCS scores or, despite >25% reduction in YBOCS score, by still experiencing significant impairment fromtheir illness.

Exclusion Criteria:

• a history of current or past diagnosis of any psychosis according to DSM-5 exceptfor OCD

• any clinical significant neurological disorder, traumatic brain injury, dementia, ormedical illness

• any contradiction of neurosurgery

• any current or unstably remitted substance abuse or dependence

• women who are pregnant or preparing for pregnant

• severe suicide risk and tendency according to the investigators' judgements

• participate in any other clinical trials within three months (except for registeredstudies).