Nerve Stimulator Appears Effective in Treatment-Resistant Depression
Dec. 15, 1999 (Cleveland) -- An implantable device that is about the size of
a stopwatch may put a stop to depression in patients who have failed treatment
with antidepressants or shock therapy. Depression affects about 18 million
Americans, but about 1 million of those people have severe treatment-resistant
depression that lasts for years and is a disabling condition.
The experimental treatment works by way of a generator implanted in the
chest. Wires attach the device to the vagus nerve, which runs from the neck
into a brain region believed to be important for regulating mood. The generator
then sends tiny electric shocks to the nerve.
The treatment, called a vagus nerve stimulator, is already FDA-approved for
severe epilepsy. But the results of a multi-center study on its effect on
depression were presented at the annual meeting of the American College of
Neuropsychopharmacology in Acapulco earlier this week and published online
Wednesday by Biological Psychiatry.
"Typically the surgery is done as an outpatient procedure that takes
about an hour or two," says lead researcher A. John Rush, MD.
Rush, vice chairman for research in the department of psychiatry at the
University of Texas Southwestern Medical Center in Dallas, tells WebMD that 40%
of the 30 patients enrolled in the open treatment trial had at least a 50%
improvement in their depression at the end of an eight-week course of
Rush says, "We have followed some of these patients for 10 months now,
and we can report that those who responded during the early phase have held the
response, and some patients who didn't respond during the eight-week trial
responded later. So the long-term results are actually slightly more optimistic
than the eight-week results that were reported in this paper."
The results are particularly compelling given the severity of depression, he
says. "Twenty-one patients had major depressive disorder and nine were
bipolar [formerly known as manic depressive]," he says. More than half of
the patients had received ECT-- the so-called electro-shock therapy -- and all
the patients failed to respond to at least two robust antidepressant medication
"A typical side effect would be a raspy-sounding voice during
stimulation, because the [vocal cords are] also affected," says Rush. The
electrical current is on for 3 seconds and then off for 5 minutes, and this
cycle is constant 24 hours a day, Rush says. "At the same time, the patient
is maintained on the baseline medication regimen. This is an unusual approach
for psychiatry, but we are considering this as an add-on therapy," he
Although he is enthusiastic, Rush emphasizes the preliminary nature of the
findings. Asked to comment on the study, Thomas Thompson, MD, director of the
ECT program at Wesley Woods Geriatric Hospital in Atlanta and assistant
professor of psychiatry at Emory University School of Medicine, echoed that
cautious note. Thompson tells WebMD, "This is very preliminary work, and
the findings need to be replicated in a larger study. A lot more work still
needs to be done."