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May 11, 2008 (Washington) - A high-tech procedure that delivers radiation
deep within the brain relieved symptoms in half of patients with
obsessive-compulsive disorder who got no help from medication or talk
therapy, a small study shows.

The procedure uses a gamma knife to target brain circuits that work overtime
in people with obsessive-compulsive disorder (OCD), says Antonio Lopes, MD,
PhD, of the University of Sao Paulo in Brazil.

"In people with OCD, the network of areas that communicate is always
working, working, working. Medication and behavioral therapy can lower the
activity of this brain circuitry. But some people don't respond, and we use
the gamma knife to try to cut the connection," Lopes tells WebMD.

Not really a knife at all, the gamma knife is a machine that emits powerful,
highly focused gamma radiation beams. This helps the doctors target a
specific area of the brain while sparing healthy surrounding tissue. It's
used to treat people with brain tumors, Parkinson's disease, and other
neurological disorders.

Gamma Knife Relieves OCD Symptoms

At the annual meeting of the American Psychiatric Association, Lopes
presented early results of a study that pits the gamma knife against a sham
procedure in 48 patients.

Two years after undergoing the procedure, two of four patients continue to
have significant relief from symptoms, he says. Their memory has improved.
And they are better able to pay attention to tasks at hand.

In contrast, there has been no improvement among patients who got the sham
procedure.

The procedure was relatively safe, with transient headaches and dizziness
among the most common side effects.

However, one patient suffered a manic episode about three months after the
procedure, which was followed by a bout of hallucinations and delusions a
few months after that.

"There are some complications, so this is not for everyone," Lopes says.
"This is for people who fail to respond to other treatments."

But for such patients, the procedure can mean the difference between being
homebound and functioning "moderately well," says David Baron, DO, professor
and chairman of psychiatry at Temple University in Philadelphia.

"These are patients who have failed every single drug and are essentially
nonfunctioning, so even a little improvement is a big deal," he says.

Baron tells WebMD that in the U.S., "surgery [for OCD] is an old idea that
is coming back because of the gamma knife. It allows you to be much more
selective and precise with less adverse effects."

SOURCES: American Psychiatric Association 2008 Annual Meeting, Washington,
D.C., May 3-8, 2008; Antonio Lopes, MD, PhD, OCD Clinics, department of
psychiatry, University of Sao Paulo, Brazil; David Baron, DO, chairman, APA
program committee; professor and chairman, department of psychiatry, Temple
University, Philadelphia.