Vagus nerve stimulation for treatment-resistant depression: is this therapy distinct from other antidepressant treatments?

Background The treatment-resistant depression (TRD) is a very disabling disease.Objective The aim of this article is to provide an overview of the therapeutic activity of vagus nerve stimulation (VNS) therapy system in TRD. We summarised the progress made during the last decade in this area.Methods We conducted a non-systematic review on the efficacy and safety of the VNS therapy for this disease. We analysed the results from acute and long-term studies that utilised this technique. Major electronic databases were searched.Results The patients with TRD may show acute and long-term benefit when treated with this technique. There are promising results for VNS therapy for these patients. The level of evidence as an acute treatment option is only 3, but as chronic treatment is 2. This therapy should be offered as an added long-term treatment option for patients with chronic and recurrent difficult to treat depression.Conclusions The antidepressant effects of this procedure remain controversial. The clinical trials have produced mixed results, but VNS therapy for TRD has two distinct features that differentiate it from other antidepressant treatments: a sustained therapeutic response obtained in highly resistant depressive disorders, a favourable safety profile and guaranteed compliance.