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More research has recently emerged showing a positive response to vagus nerve stimulation for patients suffering from depression. (See our earlier article “FDA OKs Brain Stimulator for Depression” about brain stimulation for depression and also the related article “Transcranial Magnetic Stimulation for Depression”.)

Sixteen percent to 20 percent of the group in the new study, all of whom suffered from treatment-resistant depression, experienced total remission.

Results of the study appear in the September issue of Biological Psychiatry, which also includes findings from two additional related studies.

VNS therapy, which the FDA approved for treatment of epileptic seizures in 1997 and for depression in July (“FDA OKs Brain Stimulator for Depression”), has been studied in clinical trials for treatment-resistant depression since 1998. VNS therapy includes surgical implantation of a small battery-operated pulse generator – similar to a pacemaker – in a patient’s left upper chest. Thin, flexible wires from the device are tunneled into the neck and send mild, intermittent pulses to the neck’s left vagus nerve. The vagus nerve in turn delivers these pulses about every five minutes to the areas of the brain involved in the regulation of mood, motivation, sleep, appetite and other symptoms relevant to depression.

Karmen McGuffee, who had the vagus nerve stimulator implanted in 1999 after suffering from severe depression for more than 15 years, said the device has restored her life. A participant in one of the first clinical trials at UT Southwestern, she had taken more than 10 types of antidepressant drugs before the surgery, with little success.

“It was like having the color come back into my world”, said Mrs. McGuffee, 35:

Before VNS therapy, I could barely function and only then with a lot of help. At the time, I had nothing to lose. Now I feel brighter and lighter. I’m not constantly worried, and I look forward to everyday activities. Things that other people take for granted, such as managing a house, a family and a job all are now possible.

VNS therapy is only indicated for people who have not been helped by other depression treatments, said Dr. Rush. “If you have treatment-resistant depression and need long-term treatment, VNS is an option that should be considered. While it’s not going to get everybody into remission, it’s doing pretty well in very difficult-to-treat patients”, he said.

Two of the three studies in the current journal compared patients with major depressive disorder or bipolar disorder, all of whom were implanted with the vagus nerve stimulator. In the first trial, which included 235 people and only lasted for 10 weeks, patients implanted with the stimulator received either active VNS therapy or no therapy, meaning the device was not activated. There was little change in either group.

Dr. Rush’s second multicenter trial, which included 205 of the same patients, provided active VNS therapy for a full year to all participants, measuring their symptoms of depression at regular intervals using several standard rating scales. One rating scale showed a 27.2 percent reduction in symptoms among participants and a 15.8 percent remission rate at year’s end – suggesting that long-term treatment with VNS offers a greater benefit than its short-term application. A second rating scale showed reduction in symptoms by 28.2 percent and a 20.3 percent remission rate.