The power of the placebo
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The power of the placebo

ASK THE DOCTORS

SOCIAL & LIFESTYLE
The power of the placebo

DEAR DOCTORS: We use mints to help our six-year-old with carsickness. When the mints came from the tin, they didn't help at all. But when we started keeping them in a prescription pill bottle, the "medicine" made his symptoms go away. Is this the placebo effect? Why does it work?

DEAR READER: The placebo effect occurs when someone has a beneficial outcome to a medical intervention that has no real clinical or therapeutic value. The specific form the placebo takes isn't important -- it might be a sugar pill, a saline injection or even an invented therapy. What does appear to play a key role is that the person believes the treatment can be helpful. The circumstances you described, where the mints you offered your son only became effective once they were presented as a medicine meant to cure carsickness, fit the definition.

According to historians, the placebo effect (it's also sometimes referred to as placebo response) was first described in 1799 by an English physician. More than two centuries later, countless examples of the phenomenon continue to be recorded. These include improvements in areas as diverse as physical pain and discomfort, anxiety, blood pressure, sleep disorders, heart rate and rhythms, and general well-being. And yet, despite ongoing study, the exact mechanisms behind placebo response remain a mystery.

One theory suggests that a person's prior expectations about the placebo influence their perception of how it is affecting them. For example, participants in a recent study reported getting high after consuming ordinary lollipops, which they had been told contained potent cannabis. Another idea is that the physical actions involved in receiving the placebo -- swallowing the pill, rubbing in the cream, getting an injection -- stimulate the reward centre of the brain. This, in turn, triggers the release of dopamine, the so-called feel-good hormone. Others have suggested that the expectation of feeling better due to the placebo activates a beneficial immune response.

The common denominator here is that placebos work because the recipients believe they will. But a fascinating study, published in the journal Nature six years ago, has poked a few holes in the idea. In that research, cancer patients suffering from debilitating fatigue were divided into two groups. One group received a placebo medication to treat the fatigue, and a control group received no treatment at all.

At the end of the 21-day study, when compared to the control group who received no treatment, 39% of the placebo group reported an improved quality of life. And 29% of the placebo group said the severity of their fatigue had decreased. Brain scans corroborated the patients' claims about their response to the placebo medication.

The twist here is that the group receiving the treatment knew they were receiving a placebo and not a real medication. Yet, even with that knowledge, more than one-third of them had a positive result. And this brings us back to where we began. Placebo response is a powerful example of the mind-body connection, and we are still trying to learn how it works. Universal Features Syndicate


Dr Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health.

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