Replicable effects of deep brain stimulation for obsessive-compulsive disorder

Deep brain stimulation (DBS) is a surgical treatment that can be offered to patients with severe psychiatric illness not responsive to conventional therapies. We read with interest the recent commentary in Brain Stimulation [1] that prompted ongoing debate [2] about new findings [3] in DBS for obsessive-compulsive disorder (OCD). At issue were recently implicated white matter internal capsule bundles projecting to medial and lateral frontal cortex [3,4], and how best to build on these intriguing findings [1]. Relying on the large sample size and advanced neuroimaging techniques of the Human Connectome Project (HCP) [5], the original authors used normative connectomes to identify which stimulated white matter pathways are associated with better or worse clinical response to DBS for OCD [3]. The critical commentary published in Brain Stimulation [1] critiqued an online pre-print of this normative connectome study: clinicians evaluating these tracts for purposes of treatment planning were urged to exercise caution in the absence of prospective patient-specific data, although the potential value of these tracts to future research was emphasized. Before further debating how best to interpret the final (n 1⁄4 50) peer-reviewed set of tracts [3], we asked a more fundamental question e can the association with clinical response be replicated? Just as the broader neuroscience field has started to transform in response to the ‘replication crisis,’we believe that a crucial next step in psychiatric brain stimulation research is demonstration that promising clinical and neuroimaging results can be reproduced. Given the unique risk-benefit calculus for neurosurgical procedures in psychiatry, establishing and quantifying therapeutic efficacy of DBS remains a primary concern.We therefore first sought to validate clinical utility of DBS for OCD. We report the results of DBS in OCD patients treated in New York at Mount Sinai (n 1⁄4 10; 6 male, 4 female). Prior to surgery all patients were diagnosed with serious and treatment refractory OCD (baseline Yale-Brown Obsessive Compulsive Scale (Y-BOCS) [6] mean ± standard deviation: 33.9 ± 2.6). While a variety of anatomical locations within cortico-striato-thalamo-cortical loops have been proposed as OCD targets [2], in all of these New York patients electrodes were targeted to ventral striatum or ventral anterior limb of the internal capsule. After placement of a stereotactic headframe in the operating room, intraoperative CT scans were fused with preoperative MRI to determine the approach trajectory and final lead placement. All surgeries were performed by the same neurosurgeon (B.H.K.). DBS led to 70% of patients achieving clinical response, defined in the standard fashion as a 35% Y-BOCS decrease. Y-BOCS decreased