Anxiety -- the Nerve
By Mark Moran
Sept. 24, 2001 -- Gray Scott, of Florence, S.C., has been treated for anxiety for nine years, from the time she was diagnosed with an eating disorder at age 15. Since then, she has tried a variety of medications and psychotherapy, with variable results.
"When the symptoms are alleviated, it becomes tolerable," she tells WebMD. "At their worst, I have felt very desperate."
Scott is not alone. Anxiety disorders -- including phobias, panic attacks, obsessive-compulsive disorders, and posttraumatic stress disorder -- affect more than 23 million Americans. Although treatment with a combination of drugs and therapy is very often successful, some patients go from drug to drug, and therapy to therapy, with no relief.
"Most people think of anxiety disorders as not terribly devastating, and easily treatable with drugs," says psychiatrist Mark George, MD, director of the brain stimulation laboratory at the Medical University of South Carolina in Charleston. "But there is a substantial core of people for whom drugs don't work and for whom there are no good alternatives."
That may change, however, if a new surgical treatment called vagus nerve stimulation, or VNS, proves successful.
On May 18, Scott became one of the first anxiety patients to receive the experimental treatment. On that day, surgeons at the Medical College of South Carolina implanted a device in her chest, similar to a heart pacemaker, and wired it to electrically stimulate the vagus nerve in her neck.
Named for the Latin word meaning "wandering," the vagus nerve meanders from the colon, past the intestines, heart, and lungs, and comes together at the diaphragm, where it runs as a thick cable past the esophagus and into the brain.
George calls the nerve "an information superhighway to the brain." Contrary to long-held wisdom, the traffic on that highway is mostly going north -- from the body to the brain, not vice versa, he says.
"Most people have thought of it as the way the brain controls the heart and the guts," George explains. "In fact, most of the information is actually going in the other direction. The vagus nerve is really the brain's way of interpreting what is happening in the heart and the guts."
That suggests an intriguing theoretical reason why VNS might work well for people with anxiety, he says.
"Emotions are not brain events, but the brain's interpretation of bodily events," George says. "When you feel scared, it's really your brain sensing that your heart rate is going up."
So by stimulating the vagus nerve, George and others hope to influence the exchange of information between body and brain, and thereby relieve the symptoms of anxiety.
Whether this works remains to be seen. Today, the device implanted in Scott's chest activates every five minutes, stimulating her vagus nerve with a small electrical current for a period of five seconds. When it activates while she is talking, her voice suddenly becomes mildly hoarse.
"Some days I think it's helping, and some days I don't know," she says. "At first I was expecting something instantaneous, but it doesn't work that way. It can take months to see any results."
Reason for Hope
George says there is reason for hope.
For the last 10 years, VNS has been successful treating patients with epilepsy who do not respond to conventional therapy. Stimulating the vagus nerve appears to reduce the number of daily seizures such people experience by up to 40% -- and some patients become completely seizure-free, George says.
VNS was approved by the FDA for treatment-resistant epilepsy in 1997.
VNS has also shown promise in the treatment of depression. It is approved for this use in Europe and in Canada, but not in the U.S.
In a report published last year in the Journal of the Society of Biological Psychiatry, 30 people with depression, who were not helped by common medications, received VNS. Forty percent of the patients showed some improvement after the treatment, according to the study.
Remarkably, some patients appeared to have no depression at all after the treatment.
"What got me interested was the fact that 20% to 25% of patients were completely well after treatment," says George, a co-author of the study. "Among people with treatment-resistant depression, you rarely see complete remission. These were people who had failed on three or four medications, and two-thirds of the group had had electroconvulsive therapy [ECT, the so-called shock treatment]."
A new study will compare VNS to other treatments for depression, and to no treatment. In the meantime, its apparent success with depression whets his appetite for trying the therapy with other mood disorders, including anxiety.
George says he believes there is even more reason to believe that VNS will be successful in treating anxiety because of the critical interaction between physical responses in the body -- for instance, heart rate and muscle spasms -- and the experience of fear or panic in the brain. That entire interaction occurs through the vagus nerve.
"It makes a lot of sense that you could change that interaction by manipulating the information through stimulation of the vagus," George says.
Because VNS requires surgical implantation, it is far more invasive than other electrical stimulation techniques, such as ECT or transcranial magnetic stimulation (TMS), which don't require cutting the body. And it is not cheap: The device and surgery cost approximately $20,000.
Other psychiatrists are intrigued by the success of VNS in depression, but say its practical use as a treatment remains to be seen. Richard Weiner, MD, leads the American Psychiatric Association's Committee on Electroconvulsive Therapy.
"It's an invasive technique," Weiner tells WebMD. "You need to have some justification for using it. It's never going to be something people run to do first. The issue is, once you have gone through a trial of medications, at what point do you use this?"
For Gray Scott, participating in George's study was a chance to try a cutting-edge treatment that could prove a permanent solution to the anxiety plaguing her for nearly a decade. If it doesn't work, Scott says she will have the device removed. If it does, she will leave it in indefinitely.
"It's a lot to undergo," she says. "But for people who are becoming desperate because they are not significantly relieved by medication, it's good to know you can actively try something instead of sitting around waiting."
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