Psychiatric neurosurgery teams in the United States and Europe have studied deep brain stimulation (DBS) of the ventral anterior limb of the internal capsule and adjacent ventral striatum (VC/VS) for severe and highly treatment-resistant obsessive-compulsive disorder. Four groups have collaborated most closely, in small-scale studies, over the past 8 years. First to begin was Leuven/Antwerp, followed by Butler Hospital/Brown Medical School, the Cleveland Clinic and most recently the University of Florida. These centers used comparable patient selection criteria and surgical targeting. Targeting, but not selection, evolved during this period. Here, we present combined long-term results of those studies, which reveal clinically significant symptom reductions and functional improvement in about two-thirds of patients. DBS was well tolerated overall and adverse effects were overwhelmingly transient. Results generally improved for patients implanted more recently, suggesting a 'learning curve' both within and across centers. This is well known from the development of DBS for movement disorders. The main factor accounting for these gains appears to be the refinement of the implantation site. Initially, an anterior-posterior location based on anterior capsulotomy lesions was used. In an attempt to improve results, more posterior sites were investigated resulting in the current target, at the junction of the anterior capsule, anterior commissure and posterior ventral striatum. Clinical results suggest that neural networks relevant to therapeutic improvement might be modulated more effectively at a more posterior target. Taken together, these data show that the procedure can be successfully implemented by dedicated interdisciplinary teams, and support its therapeutic promise.

These preliminary findings demonstrate that DBS may have important therapeutic benefits on psychopathology in OCD. No harmful side-effects were detected during follow-up (33/33/39 months, respectively).

A two-day consensus conference was held in order to examine scientific and ethical issues in the application of deep brain stimulation in the treatment of mood and behavioral disorders such as major depression, obsessive-compulsive disorder, and Tourette syndrome. The primary objectives of the conference were to 1) establish consensus among participants about the design of future clinical trials of DBS for disorders of mood, behavior and thought and 2) develop standards for the protection of human subjects participating in such studies. Conference participants identified 16 key points for guiding research in this growing field.