Vagus nerve stimulation and depression

Vagus nerve stimulation (VNS) is an old, yet new, option for treatment-resistant depression. Despite several clinical trials over the last 15 years showing a consistent benefit-risk balance of the technic, VNS still struggles to find its place in our therapeutic algorithms. This is especially true in France, where only a few surgeries have been performed nationwide, all in the last year. The reasons behind this lag are manifolds; (1) psychiatrists usually do not consider surgical treatments, even when they are minimally invasive and reversible, (2) early VNS trials stumbled on methodological difficulties that are common to all invasive neurostimulation technics, and initially failed to provide strong evidence for its efficacy, and (3) VNS requires multidisciplinary teams involving psychiatrists and neurosurgeons that did not exist then. Nevertheless, studies of the past twenty years support VNS as a treatment of depression endowed with a unique efficacy profile: a long runner best at maintaining remission in hard-to-stabilize depression, even in the context of ECT withdrawal, and irrespective of whether it is unipolar or bipolar. Thus, VNS potentially addresses the unmet medical needs of some of the most severe and chronic patients with depression. This review aims at introducing VNS as a treatment option for depression, summarizing available evidence for its efficacy and tolerance, and delineating patient profiles that might benefit the most of such treatment.