- Placebos often make people feel better, but for decades,
researchers didn't try very hard to figure out why. A sugar pill, after
all, isn't likely to become a best-selling drug or turn a scientist into
a star. But now, a new generation of psychiatrists and neurologists is
trying to solve the mystery of the placebo.
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- Why do placebos help some people and not others? How
can researchers study placebos without violating medical ethics? As neuroscientist
Melanie Leitner put it before an audience of scientists last month, "What
does it mean to harness the power of belief?"
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- "There really hasn't been a whole lot of research
on the placebo," said epidemiologist Dr. John Bailar, professor emeritus
at the University of Chicago. "There's a lot of description and a
lot of chatter, but we don't know a whole lot about it."
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- One thing seems to be clear, however. The brain is a
"crucial player," said Leitner during a workshop on placebos
at a February meeting of the American Association for the Advancement of
Science.
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- "What we need to learn is how taking a placebo affects
the brain's processing of symptoms and other sensations related to illness,
how it affects output and the activity of your immune system," said
Dr. David Spiegel, a Stanford University psychiatrist who studies placebos.
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- Research has shown that people who unknowingly take placebos
-- sometimes pills, sometimes injections -- often feel relief from pain,
cardiovascular disease, gastrointestinal disorders and high blood pressure.
But placebos don't help people recover from diseases like cancer. "They're
more likely to be effective when there's a perceptive component to the
illness," Spiegel said.
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- Some experts say the placebo effect is indeed all in
your head, but they aren't too impressed by the idea. "Many people
see placebo as just about that doctor-patient relationship, that laying
on of hands, that trust," said Dr. Helen Mayberg, a neuropsychiatrist
at Emory University. They claim "that placebo is some kind of poor
man's psychotherapy. It's just the interaction, and any interaction is
good."
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- But she thinks there's more to it than that. She and
colleagues examined brain scans of three groups of depressed people --
those who took placebo antidepressants, those who got cognitive therapy,
and those who took actual Prozac pills. Several patients who took placebos
felt better, and the scans showed their brains reacted like those of subjects
in the antidepressant group, but not those who went through "talk"
therapy.
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- In other words, placebos seemed to work on the parts
of the brain that are also affected by actual drugs. But, Mayberg said,
the placebos weren't as powerful as Prozac, and their effects didn't last
as long. "The drug is not equal to placebo. The drug is placebo-plus,"
she said.
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- Mayberg's study, published in 2002, raises the possibility
that many drugs come with a built-in placebo effect, perhaps boosted by
their active ingredients. Some experts go even further. "An awful
lot of alternative medicine is a placebo effect and I think a lot of standard
medicine is also the placebo effect," said Dr. Howard Brody, a bioethicist
at Michigan State University and author of a book on placebos.
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- But people who take placebos don't always get better,
and in some cases, they actually feel worse. In recent years, researchers
have begun exploring the so-called "nocebo" effect: People who
take placebos sometimes develop the side effects of the drugs they think
they're taking. ("Nocebo" is Latin for "I will harm";
"placebo" means "I will please.")
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- The nocebo effect, the dark side of placebos, presents
yet another puzzle for researchers to solve. There are two possibilities,
said Dr. Arthur J. Barsky, a psychiatrist at Boston's Brigham and Women's
Hospital. First, the patients may be reacting to suggestion. One study
found that the number of aspirin users reporting gastrointestinal problems
jumped by six times when they were told that the symptoms might be a side
effect of their treatment. Second, something may be happening in the neurons
of the brain itself, Barsky said.
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- But how can researchers test these theories? The typical
way to test a new medication is to split a group of subjects in two, give
the medication to one half and a placebo to the other, and see what happens.
Typically, all the patients must be told what's going on. It's unethical
to tell patients they're all getting an actual drug when they might be
gulping sugar pills.
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- Scientists studying placebos could conceivably divide
subjects into two groups -- those getting placebos and those getting nothing.
But thanks to informed consent, everybody would be able to figure out which
group they're in. Placebos don't seem to work when people know they're
taking a sham drug.
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- The other alternative is to keep testing placebos against
regular drugs, but that's an iffy proposition, too, said Bailar of the
University of Chicago. If patients know they are likely to receive a placebo,
that knowledge may sharpen their interest and alter their responses.
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- Even if researchers do untangle the workings of placebos,
it's not clear what they'll be able to do with the information.
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- "You wouldn't have a pharmacist selling placebo
pills to the public," Bailar said. But he thinks more knowledge about
how placebos work might help people better understand how individuals react
to medication and help doctors do a better job of prescribing drugs.
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- Many doctors, he said, essentially prescribe placebos
all the time. "The doctor knows this (drug) isn't going to do anything
for the patient, but the patient came expecting pills, so this is a way
to please them. Who knows? Maybe it will work."
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- Perhaps doctors will learn which drugs rely more on the
placebo effect than anything else, he said.
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- Whatever happens, Bailar is hopeful about the growing
research into placebos. "I have a pretty deep faith that wherever
it's heading is someplace we want to go," he said.
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