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Sedric
Bell's brain releases compounds that alleviate the symptoms
of his Parkinsons even when he receives a sham injection. |
At
the University of British Columbia Hospital in Vancouver, Dr.
Jon Stoessl set out to study real drugs treating Parkinson's
disease. In "Expectation Pays," Stoessl explains to Alan how he
wound up with startling new evidence about how placebos affect the
brain instead.
Parkinson's
affects the central nervous system and causes debilitating muscle
stiffness and rigidity, as well as the tremors often associated
with the disease. The standard treatment for Parkinson's is a drug
that stimulates the brain to release dopamine, a crucial brain chemical
that helps control movement. Patients respond well to this course
of treatment in the beginning, but after several years, the benefit
of the medication deminishes.
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| This
MRI machine measures Bell's response to "real" and
placebo injections.. |
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As
part of a study to determine the effectiveness of a new medication,
Stoessl measured how much dopamine is released in response to the
drug. But Parkinson's is well-known to be alleviated - at least
for a little while - by placebo. So Stoessl had to administer both
the real drug and placebo to the patients in his study. Each patient
received three or four injections, one of which would be an inert
substance - the placebo. Patients were informed that one of the
injections was a placebo, but they wouldn't know which one it was.
As
expected, the trial drug induced a dopamine release in the brains
of the study's subjects. Surprisingly, however, the placebo injection
induced just as big a dopamine release. Moreover, the dopamine release
occurred in precisely the same place in the brain as it does with
the real drugs - exactly where it's needed to help control movement.
According
to Stoessl, "this is a tremendous example of the mind controlling
the body. . .This is the classic example of how your expectation
of something, your attitude toward something can materially affect
the physical outcome."
For
more on this topic, see the web feature:
Medicine Men and the Puzzling Placebo
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