Long-Term DBS for Obsessive Compulsive Disorder: Promise, Progress, and Pitfalls

DBS of the ventral capsule/ventral striatum (VC/VS) for otherwise treatment- intractable OCD, a therapy which originated in Belgium in 1998, began in the US in 2001. The FDA approved its humanitarian use in 2009. That approval was based in part on open-label pilot data from from three US centers (Butler Hospital/Brown Medical School, Cleveland Clinic, University of Florida). The original pilot patients have now been followed for up to eight years after implantation. Those longer-term data suggest that, once obtained, therapeutic effects of VC/VS DBS were generally sustained during continuing stimulation. Typically, symptoms improved from the “very severe” to “moderate” range, paralleled by gains in daily functioning. Long-term outcomes are important in understanding risks, benefits, and burdens of these intensive treatments.  About one-third of DBS patients no longer received  simulation three-plus years after implantation. Therapeutic benefit was broadly similar to that seen after lesion procedures, although ablations and DBS impose different risks and burdens. Patients whose OCD symptoms were primarily based in avoidance of harm seemed to benefit most. Improvements in co-occurring depression and non-OCD related anxiety preceded the maximal improvement in OCD symptoms. Conversely, worsening in depression and nonspecific anxiety usually preceded OCD worsening when DBS was interrupted. As for lesion procedures, patients were able to benefit from exposure-based psychotherapies after DBS began when they could not do so before surgery. All of these clinical observations shaped our hypotheses that behavioral phenotypes, and brain circuits, related to fear, avoidance of fear, and also rewarding experiences are important in the therapeutic response to neurosurgery for OCD. This is the focus of ongoing translational research by our collaborative group, supported by the National Institute of Mental Health, which we expect will lead to improved surgical targets and stimulation methods. Clinically, long-term data, with larger patient groups are essential to optimizing patient selection and management for current OCD surgeries. Our ongoing controlled clinical trial of DBS for OCD, also supported by the NIMH, will help in obtaining such data. But creation of a national/international data registry, suggested by ourselves, other investigators, and the NIMH is essential to realize the promise of this field.