Vagus nerve stimulation

VNS, as delivered by the NCP system, is an FDA-approved, well-tolerated, effective intervention for a substantial proportion of patients with treatment-resistant epilepsy. Its longer term safety and tolerability are well documented in these patients. There are several clinical and theoretical reasons to think that VNS might be an effective antidepressant or mood stabilizer. A recent open, uncontrolled trial provided encouraging results. Most patients who responded acutely have maintained the benefits. Some subjects responded after exiting the acute study, while continuing to receive VNS in an uncontrolled follow-up. These results are similar to the increasing benefits with VNS over the longer term observed in patients with epilepsy. Major questions ranging from the need to establish efficacy in a controlled, comparative trial; determining indicators of who will respond; documentation of long-term efficacy; studies of cost recovery; and where VNS fits into the overall disease management scheme for depression deserve careful study.