MONDAY, March 19 (HealthDay News) -- A small new study gives
insight into how electroshock therapy, an effective yet poorly
understood treatment for severe depression, affects the brains of
Researchers used functional MRI scans to look at brain activity
in nine adults with severe depression before and after electroshock
therapy. The investigators found that electroshock, or
electroconvulsive therapy (ECT), dampens the connections between
different areas of the brain in depressed people.
"With our study we were able to confirm that there is hyperconnectivity [in depression], and in addition we could show that treatment removes it," said study co-author Christian Schwarzbauer, a professor of neuroimaging at the University of Aberdeen in Scotland.
Although it may seem counterintuitive that people with severe
depression, who are often also lethargic, would have brains on
overdrive, one explanation could be that they have too much
internal brain activity and cannot deal as well with external
stimulation, Schwarzbauer said.
This study could point to ways to improve electroshock therapy's
effectiveness and safety, he added. In its 76-year history, the
treatment has met with opposition from doctors because of concerns
of its side effects, such as memory loss.
Electroshock therapy is typically only used for patients who
have not responded to antidepressants or other types of treatment
and are at risk of hurting themselves or others.
"I think the fact that now there's more of an explanation, I think that's reassuring to the clinician as well as the patient," said Jennifer Perrin, who is a research fellow at the University of Aberdeen and lead author of the study published online March 19 in the Proceedings of the National Academy of Sciences.
For the study, nine severely depressed participants underwent
functional MRI scans of their whole brain before and after a series
of electroshock therapy. They received the treatment twice a week
until their symptoms, including sadness and fatigue, subsided.
The participants had not responded to antidepressant drugs
before the study or received electroshock therapy in the past six
months, although four of the patients were taking antipsychotic
The researchers zeroed in on an area in the front of the brain
called the dorsolateral prefrontal cortex. It had fewer and less
intense connections with a number of other areas of the brain
following electroshock therapy, the scans showed.
This particular part of the brain is involved in cognition
[thought processes] and social behavior and has been implicated in
depression, so this finding is not surprising, said Tony Tang, an
adjunct professor of psychology at Northwestern University. What is
surprising, he said, is that none of the many other brain areas
that have been associated with depression were found to have
cut-off lines of communication following electroshock therapy.
"ECT is a rather invasive, drastic procedure and you see a lot of changes in patients, so we would probably speculate that there would be some sort of widespread brain connectivity changes," Tang said. This study "found it to be localized, and I found that to be rather amazing."
During electroshock treatment, clinicians place electrodes on
the scalp and, while the patient is under anesthesia, deliver
enough electric current to induce a seizure. The therapy is more
effective when electrodes are on both sides of the head, as opposed
to just one, but unfortunately this also carries greater risk of
Having electrodes on both sides of the head may be more
effective because it triggers a more widespread seizure, but the
current findings suggest another possibility, Tang said: When
clinicians put electrodes just on one side of the scalp, they
usually put them over the right half of the brain because it is
less dominant (for right-handed people). However, according to this
study, the dorsolateral prefrontal cortex, in the left side of the
brain, could be the crucial area to target.
"Most localized forms of stimulation we've tried so far don't work as well [as having electrodes on both sides], but this type of study could potentially point to the right direction," Tang said.
Looking at brain connections in people with severe depression
could help clinicians predict who will benefit from electroshock
therapy as well as who will relapse after treatment, Schwarzbauer
suggested. Between about 60 percent and 80 percent of people become
depressed again, usually within six months of the treatment.
Beyond depression, functional MRI of the entire brain could
offer insights into other conditions that could be related to
changes in brain networks, including autism, schizophrenia and
dementia, Schwarzbauer said.
The U.S. National Institute of Mental Health has more on
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