Vagal Nerve Stimulation in Treatment of Refractory Major Depression

Vagal nerve stimulation (VNS) for treatment of refractory major depression (TRMD) has been explored as an alternative to electroconvulsive therapy and ablative neurosurgery. VNS describes a procedure whereby the cervical portion of the left vagus nerve (VN) is stimulated electrically. A robust assessment of the "adequacy" of treatments (pharmacological, psychological, and ECT) must be conducted before a surgeon is approached to consider implantation of a VNS system. This chapter provides a list of measures, or suitable alternatives, which usually forms the core of a comprehensive assessment battery for patients with refractory major depression who are to be treated with VNS. VNS therapy has also been shown, using functional magnetic resonance imaging in major depressive disorder (MDD) patients, to be associated with ventromedial prefrontal cortex deactivation and activation of the right insular cortex. All patients should be kept under close clinical review and, where appropriate, clinical outcomes should be fully reported.