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Learn about Vagus Nerve Stimulation (VNS Therapy) for treatment-resistant depression. How VNS works, side-effects, and whether it's an effective depression treatment.
Vagus Nerve Stimulation may be the possible successor to ECT (Electroconvulsive Therapy). In July 2005, the VNS Therapy System was approved by the FDA for depression patients who have run out of treatment options despite controversy on whether it even works. The criteria for approval is, a patient must:
- be age 18 or older.
- have treatment-resistant depression.
- have long-term, chronic depression that has lasted two or more years.
- have recurrent or severe depression.
- depression hasn't improved after the use of at least four other treatments, such as four different antidepressants.
Keep in mind that Vagus Nerve Stimulation doesn't guarantee that your depression symptoms will get better. The FDA advises that vagus nerve stimulation be used only along with traditional depression treatments such as antidepressants and psychotherapy.
Earlier VNS Clinical Trials
 In July 2003, Cyberonics, which manufactures the VNS device, announced that the Vagus Nerve Stimulator is effective in treating severe, treatment-resistant depression. That followed completion of a 235-patient clinical study of the safety and efficacy of vagus nerve stimulation (VNS Therapy) in patients with chronic or recurrent depression in the United States and Canada. In the study, subjects had a pacemaker-like pulse generator, called the VNS Therapy System, implanted under the skin in the upper left chest. A stimulation electrode connected to the generator is tunneled from the chest to the neck where it is attached to the left vagus nerve.
Previously, Cyberonics conducted a 60-patient pilot study of the safety and efficacy of the vagus nerve stimulation (VNS Therapy) in patients with chronic or recurrent depression. Results of the acute phase of the study indicated substantial improvement. In an abstract from the study, researchers say "positive open trial results in a severe, treatment-resistant depression patient group suggest that VNS is a safe and effective treatment for a significant proportion of these patients."
One Happy Customer
One news report cites Lauri Sandoval, 42, a participant in the pilot study, who has tried almost every antidepressant available and was set to start electroconvulsive therapy: "I was so desperate and depressed that I wasn't even scared of it, even though it hadn't been studied before."
Lauri had suffered from depression for 30 years and was having trouble holding down a job. It took her three months after receiving the implant to feel the change, and 18 months later, she reported feeling dramatically better:
"I used to be a hermit and I tried to pretend that I wasn't depressed. I would stay in bed as long as I could. I would get up to go to work, or to walk my dogs, but after a while that would even be difficult."
VNS Therapy Isn't Cheap. Who Will Pay?
Another potential drawback may be the cost involved. The VNS device costs $15,000 and the cost of surgery to implant the device can run as high as $15,000. In June 2007, the U.S. Centers for Medicare and Medicaid Services issued a final decision saying the government will not cover Vagus Nerve Stimulation. It's reason: "CMS has determined that VNS is not reasonable and necessary for the treatment of resistant depression." One day, insurance companies may find this is more cost-effective than antidepressant medication or talk therapy over the long term, but some say they won't be quick to pick up the tab. (The Cyberonics website lists 335 insurance carriers as of September 2008 who will consider payment on a case-by-case basis.)
Background on VNS Therapy
Vagal nerve stimulation was initially developed and approved by the FDA for the treatment of refractory partial onset epilepsy. Then reports came in that VNS in patients with epilepsy was associated with an improvement in mood. As a consequence, VNS was also investigated as a treatment for refractory depression (treatment resistant depression). The potential antidepressant effect of VNS has been reported to be most effective in patients with low-to-moderate, but not extreme, treatment-resistant depression.
Regarding the use of VNS for the treatment of refractory depression, Rush, et al. (2000) reported on an uncontrolled case series involving 30 adults with treatment-resistant major depressive disorders who underwent a 10-week trial of VNS. A positive response, defined as at least a 50% decrease in baseline score of the Hamilton Depression Rating Scale, was noted in 40% of patients.
Many other studies concur that VNS is indeed effective in tough-to-treat depression. However, these findings don't take into account improvements over time in patients without the device. In the only randomized controlled trial, Vagus Nerve Stimulation failed to perform any better in implanted patients who had the device turned on versus those whose device was inactive.
What Can You Expect From VNS Therapy for Treatment-Resistant Depression?
Vagus Nerve Stimulation hasn't been on the market that long, so long-term studies aren't available. That's why it's extremely important to discuss the pros and cons of VNS Therapy with your psychiatrist and other doctors. As mentioned earlier, the FDA advises that VNS be used only along with traditional depression treatments such as antidepressants and psychotherapy.
It may take several weeks to months before a VNS patient notices improvement in their depression symptoms. And since VNS didn't perform any better than a placebo in clinical trials, it's possible a patient won't experience any improvement at all. In fact, the FDA advises that, in some cases, depression could worsen with VNS therapy. The most common adverse effect (side-effects) associated with VNS is voice alteration or hoarseness, throat pain and cough. Dyspnea and paresthesia are also reported side-effects of Vagus Nerve Stimulation. Vagal nerve stimulation has not been reported to cause cognitive impairment.
Other VNS Therapy Stories:
Sources:
- George, Mark S. et al (2000). Vagus Nerve Stimulation: A New Tool for Brain Research and Therapy. Biological Psychiatry, 47
- Doctor's Guide, Vagus Nerve Stimulation Successful For Depression, December 16, 1999
- Cyberonics website. September 2008
next: Vagus Nerve Stimulation For Depression
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