Long Term Follow-up of Deep Brain Stimulation for Treatment-Resistant Depression

The U.S. lifetime prevalence of major depressive disorder (MDD) is 17%. A number of treatments are available for depression including medications, psychotherapy and various somatic treatments. Unfortunately, up to two-thirds of patients remain symptomatic following first-line treatment and a third fail to achieve remission (defined as full resolution of depressive symptoms) after four established treatments; approximately 10%-20% of depressed patients may show virtually no improvement despite multiple, often aggressive treatments. Thus, a conservative estimate places the U.S. prevalence of treatment-resistant depression (TRD) at 1%-3%. TRD has a high risk of suicide, is a major cause of disability and is responsible for doubling of overall health care costs. For patients with TRD there are limited evidence-based treatment options. Transcranial magnetic stimulation (TMS) may have efficacy for patients that have failed no more than one antidepressant medication 10-12, but response and remission rates are relatively low (under 30% and 20% respectively). Vagus nerve stimulation (VNS) may have efficacy in patients that have failed 4-6 antidepressant treatments but long-term response and remission rates are again low (about 20% and 10% respectively). Electroconvulsive therapy(ECT) can be effective in TRD patients with remission rates of 50%-60%. However, more than 70% of TRD patients will relapse within 6 months following a successful acute treatment course. For patients that have failed ECT, there are no evidence-based treatment options. Therefore, there is great need for novel treatment approaches for TRD. Prior clinical trials have shown that SCC DBS has the potential to be a valuable treatment option for patients with TRD. Further developing this treatment will involve confirming its effectiveness and identifying ways to optimize its use. In this study the investigators intend to test the safety and efficacy of chronic SCC DBS as a treatment for TRD and compare the safety and efficacy of left-sided versus right-sided stimulation using a double-blind, randomized, cross-over design.