Vagus nerve stimulation in treatment-resistant bipolar depression

Vagus Nerve Stimulation (VNS) is a brain stimulation technique approved as augmentative treatment of drug-resistant depression (TRD). To date, however, the efficacy of VNS has been mostly investigated in unipolar depression and, only to a minor extent, in bipolar depression. However, given that VNS was first introduced in the treatment of refractory epilepsy due to its anticonvulsant properties, it would be of clinical interest to specifically assess the efficacy of this technique in patients with Bipolar Depression, and to evaluate not only its antidepressant effect but also its potential mood-stabilizing properties in the long-term. The present article provides a brief description of the technique and presents the preliminary results at 6 months of 4 patients with Bipolar Disorder and TRD treated with VNS therapy. In addition, hypotheses of potential mechanisms underpinning the efficacy of VNS in Bipolar Disorder are provided and discussed.