Placebo's power goes beyond the mind

Even though medical researchers told Chuck Park that he might be getting a sugar pill, the 30-year-old software producer was pretty sure he was getting the real thing. Just a few weeks into the clinical trial, Park’s depression started to lift. He began to feel less anxious and sad.

So when Park learned he’d been taking a placebo all along, it was a surprise.

“I was fully expecting to receive the real drug even though I knew that the placebo was a possibility,” remembers Park of Culver City, Calif. “I guess I wanted it to work — and in a way, it did.

For years, scientists have looked at the placebo effect as just a figment of overactive patient imaginations. Sure, dummy medications seemed to curb epileptic seizures, lower blood pressure, soothe migraines and smooth out jerky movements in Parkinson's — but these people weren't really better. Or so scientists thought.

Now, using PET scanners and MRIs to peer into the heads of patients who respond to sugar pills, researchers have discovered that the placebo effect is not "all in patients' heads" but rather, in their brains. New research shows that belief in a dummy treatment leads to changes in brain chemistry.

"There have always been people who have said that we could make ourselves better by positive thinking,” says Dr. Michael Selzer, professor of neurology at the University of Pennsylvania School of Medicine. “After pooh-poohing this for years, here are studies that show that our thoughts may actually interact with the brain in a physical way."

New insights into how placebos work may even help scientists figure out how to harness the effect and teach people to train their own brains to help with healing.

Mind over brain matter
Recent reports show that anticipation of relief from a placebo can lead to an actual easing of aches, when the brain makes more of its own pain-dousing opiates. Brain scans of Parkinson’s patients show increases in a chemical messenger called dopamine, which leads to an improvement in symptoms when patients think — mistakenly — that they are receiving real therapy.

‘Pain is not in the muscles or the arm that may be injured. The pain is in our brains.’ — Dr. Sean Mackey Stanford University

And studies in depressed patients like Park have found that almost as many are helped by placebo treatments as by actual medications. In fact, as it turns out, a person’s response to placebo treatment may offer clues as to whether “real” treatments with antidepressants are likely to work.

Researchers are just starting to appreciate the power that the mind can have over the body, says Tor Wager, an assistant professor of psychology at Columbia University.

“An emerging idea right now is that belief in a placebo taps into processes in your brain that produce physical results that really shape how your body responds to things,” he says. “The brain has much more control over the body than we can voluntarily exert.”

INTERACTIVE The brain An interactive road map to the mind

As an example of this, Wager points to the body’s response to perceived threats.

“Say it’s late at night and everything is quiet and then suddenly you see someone outside, near a window,” he explains. “Your body starts to respond. Your pupils dilate. Your heart rate goes up. You start to sweat.”

The belief that something threatening is out there produces a host of physical responses that you have little control over. If you were told to calm down and turn off these sensations, you couldn’t, Wager says. “But if the belief changes — say, it turns out that it’s just your husband coming home — the physical response changes.”

The question, now, is how to tap into these powerful, unconscious responses, Wager says.

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