NEW YORK, Dec 16 (Reuters Health) -- A surgically implanted device that
stimulates the vagus nerve shows promise for treating patients with severe,
treatment-resistant depression.
The vagus nerve, a nerve that runs between the brain and the trunk of the
body, has many functions, including carrying nerve impulses to areas of the
brain that play a role in mood and sleep.
The vagus nerve stimulator (VNS) is implanted in the chest and delivers
an electric pulse to the nerve as it runs through the neck every five minutes.
The device has successfully been used to treat epileptics with hard-to-control
seizures.
In a new study, Dr. A. John Rush of the University of Texas Southwestern
Medical Center at Dallas and colleagues implanted a VNS device in 30 patients
with severe depression or bipolar disorder resistant to treatment with
medication or electroconvulsive therapy. The device stimulated the vagus nerve
for 8 weeks at the maximum, comfortably tolerated dose for each patient.
About 40% of the patients responded to the treatment, showing at least a
50% improvement on depression rating scales. In addition, some patients showed
"substantial functional improvement," being able to return to work or other
daily activities, Rush's group reports in an online abstract of a Biological
Psychiatry paper which is due to be published in a February issue of the
journal.
"VNS is a safe and effective treatment for a significant proportion of
these (severe, treatment-resistant) patients," the investigators conclude.
In an interview with Reuters Health, Rush said that his group has
"followed the patients out to as long as a year and so far so good... They have
basically maintained the response." He added, "We need to get more data to make
sure this is maintained."
The study will be expanded to include 60 patients, he said. Because most
of the patients stayed on antidepressant medications during the study, Rush said
that VNS "could either independently be an antidepressant" or it might work in
tandem with antidepressant drugs.
He also noted that the treatment "does not change normal moods. (Patients)
have normal reactions to normal events."
