By PT Staff, published on May 1, 2000 - last reviewed on June 9, 2016
There's hope for the near million Americans suffering from
untreatable depression. Results of a recent pilot study suggest that
electrical stimulation of a specific nerve may succeed in combatting the
most devastating forms of the blues those that have resisted medications,
psychotherapy and other treatments.
The vagus nerve passes from the brain through the neck and into the
abdomen, delivering information to and from brain regions that control
mood, sleep and other functions. Researchers at four different sites
implanted a small pacemakerlike device in the chests of 30 patients,
tunneled wires from the device to the vagus nerve in patients' necks,
then set it to deliver a small electrical pulse at five-minute intervals.
Vagus nerve stimulation (VNS) alleviated depression in 40% of subjects
during the eight-week study and, better still, halved the symptoms of 57%
within six months.
"Half better means that somebody who was only sleeping one or two
hours a night is now getting a full night's rest," says study co-author
Mark George, M.D., professor of psychiatry at the Medical University of
South Carolina. "That is a big thing when you are starting so deep in the
hole." In order to qualify for the study, patients had to have suffered
from major depression for over two years and to have failed to respond to
at least two rounds of antidepressants and at least six weeks of
George believes that VNS triggers changes in the brain's
neurotransmitter output, though exactly how this happens isn't yet
certain. In the meantime, it's clear that the device will be an important
new weapon for treating the blues.
In this age of MTV-inspired rapid-fire images and sound bites, we
are bombarded with more information than we can handle. How do we
separate the refrigerator's hum from the phone's ring?
Yale neurobiologist Nenad Sestan, M.D., has identified a mechanism,
called the Notch signaling pathway, that may provide the answer. Here's
how it works: Each neuron we have represents part of a memory or
association. Neurons grow cordlike extensions called axons and dendrites,
collectively called neurites, that attach to other neurons. The more
connections a neuron has, the more it is fired, reinforcing the memory it
represents. Sestan has found that neurons surreptitiously fight to win
the brain's attention by triggering the Notch receptor on neighboring
cells, impairing these cells' ability to extend neurites so they can't
communicate as well with the brain.
Sestan isn't sure how neurons know which cells to deactivate. But
considering how much information we tune out daily, they're doing a good
job--notwithstanding that TV jingle stuck in your head.
Living with Obsession
One reason: Awareness of OCD is at an all-time high. "We've seen an
increase in the number of people coming for treatment," says Sheila
Woody, Ph.D., director of the Yale University psychological services
clinic. The media may be partially responsible for educating the public
about OCD, adds Stephen Josephson, Ph.D., clinical assistant professor at
Cornell Medical School. "They are illustrating that there are available
treatments." This means scientists can better study and treat it,
something they're already striving to do: Yale just added group treatment
for OCD to its psychological services; New York University recently
announced the creation of a center devoted to the study of neurological
disorders, including OCD; and University of Nebraska researchers are
examining ways to combat the disorder in schools. To learn more, visit
the Obsessive Compulsive Foundation at ocfoundation.org.