Long-term outcomes of subcallosal cingulate deep brain stimulation for treatment-resistant depression

Objective: Deep brain stimulation of the subcallosal cingulate (SCC DBS) has been studied as a potential treatment for severe and refractory major depressive disorder since 2005. The authors used an open-label, long-term follow-up design to examine participants enrolled in a clinical trial of SCC DBS for treatment-resistant depression. Methods: Long-term outcome data were collected for 28 patients (20 with major depressive disorder and seven with bipolar II disorder; one patient in the major depression subgroup was later reclassified as having bipolar II disorder) receiving SCC DBS for 4-8 years. Results: Response and remission rates were maintained at $50% and $30%, respectively, through years 2-8 of the follow-up period. Three-quarters of all participants met the treatment-response criterion for more than half of their duration of participation in the study, with 21% of all patients demonstrating continuous response to treatment from the first year onward. Of 28 participants, 14 completed $8 years of follow-up, 11 completed $4 years, and three dropped out before 8 years. The procedure itself was generally safe and well tolerated, and there were no side effects of acute or chronic stimulation. The rate of medical or surgical complications was consistent with the rate observed in studies of DBS for other indications. There were no suicides. Conclusions: In .8 years of observation, most participants experienced a robust and sustained antidepressant response to SCC DBS.