The U.S. Food and Drug Administration has approved the vagus nerve stimulator (VNS) implant for treatment of depression. This device is used when other treatments for depression have not worked.

A generator the size of a pocket watch is placed in the chest. Wires go up the neck from the generator to the vagus nerve. The generator sends tiny electric shocks through the vagus nerve to that part of the brain that is believed to play a role in mood.

How well the VNS implant works has not been well studied and the device is expensive.¹³