A new study by researchers at Washington School of Medicine in St. Louis offers new insight into why vagus nerve stimulation (VNS) is so successful in treating persons with severe depression. VSN involves inserting a device into the upper left area of the chest to stimulate the left vagus nerve, which originates in the brain. A preprogrammed generator then delivers timed electronic pulses to the nerve. VNS was approved by the Food and Drug Administration in July 2005 for treatment-resistant depression.
Previous studies showed that the technology was successful in treating people with severe depression—who had not responded to antidepressants and had been depressed for as long as 20 years–but it was unclear how the stimulation worked. Now new research offers some preliminary explanations as to what, exactly, the device does inside the brain that improves depression.