Vagal Nerve Stimulation for Treatment Resistant Major Depression

Implantable VNS (iVNS), the electrical stimulation of the nervous system to modulate or modify function, has been FDA approved in the United States since the late 1990s. Implantable VNS therapy has been approved for use in epilepsy and depression. When treating major depression with implanted VNS, the widely held belief is that chronic stimulation is required for therapeutic effect. In trials of implantable VNS in major depression, more patients respond at 12 months than at 3 months. Once depressed patients respond to VNS, the effects have been demonstrated to continue for up to five years with continued stimulation. This finding suggests that VNS gradually changes brain function through neuroplasticity.