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Thursday, May 08, 2008

Placebo effect: Your mind's role in your health

Recently, a group of writers from The Word Guild got together and contributed essays to a book, Hot Apple Cider. I offered an essay that looked at some of the findings from The Spiritual Brain - what I learned about how mental states affect physical health. Here's part of my reflection, for your enjoyment:

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You probably aren’t waiting for science to come up with “the perfect pill for every ill,” but if you know anyone who is, he or she likely will be waiting a long time. Not because dramatic science discoveries will fail, but because the effect of many medical treatments depends at least in part on the patient’s expectation. Doctors know this by experience, of course, but research has shed new light on how powerful the patient’s expectation is.

In 2004, University of Michigan researchers reported on a study of pain experienced by healthy young male volunteers. To induce pain, they injected saltwater into their volunteers’ jaws and measured the impact by positron emission tomography (PET). They then gave the volunteers a substance described as pain relief. Not only did the volunteers report feeling better thereafter, but a number of brain regions that activate when we experience pain showed a reduced response. In other words, there was external evidence that the volunteers’ subjective belief that they felt better corresponded to the reality of pain signals in their brains.

However, … and this is the key point … no pain relief drug had actually been used in the study! The volunteers felt less pain simply because they believed they had received a powerful drug. The researchers commented that their study demonstrates how our perceptions truly affect the amount of pain we experience. This study, along with many others, showed that the effect of what we believe is real and measurable in scientific terms.

This effect is usually called the placebo effect, after a Latin phrase meaning “I will please.” Some researchers prefer to call it the “meaning effect” or the “remembered wellness” effect. Whatever its name, the meaning you attach to a treatment helps determine how effective that treatment will be for you.

For example, anthropologist Daniel Moerman of the University of Michigan notes that various studies have shown that large pills work better than medium-sized pills and four pills work better than two, even when all the pills are sugar and all the injection are sterile water. And culture can make a difference in the relief we experience too. North Americans tend to believe that injections are more powerful than pills, so injections of sterile water may provide us more relief than a sugar pill (even though both are placebos). But that does not work for Europeans who do not think that injections are more powerful than pills. Blue sleeping pills work better than other colors—except when given to male Italian soccer fans whose team colour is blue.

Even sham surgery works. Sylvester Colligan of Beaumont, Texas, could barely walk before his 1994 knee operation. He was mobile and free of pain six years later. But, as he later learned, he was actually in the control group. Yes, he received three knee incisions, but he was just sewn up again afterward; no conventional arthroscopy was done. But his body did not know that because his mind did not.

Similarly, a 2004 study compared 30 patients who received controversial embryonic stem-cell implants for Parkinson’s disease to patients who received only sham surgery. The patients who thought they had received the stem cells reported better quality of life a year later than those who thought they had received the sham surgery—regardless of which surgery patients had actually received. Ratings by medical personnel tended to concur with the patients’ own views. That last point is significant. The more your doctor believes in a treatment, the more likely you are to experience relief from it.

At one time, doctors suspected that more emotionally expressive people responded more strongly than stolid souls, but that does not seem to be the case. Our minds are real, and what we expect to happen is important.

Still, there are limitations on the power of our minds. Placebos do not help to treat cancer (though they help cancer patients with appetite and pain control). Also, only a person who is intellectually capable of believing that a medication provides relief can experience the effect of hope. One study found that Alzheimer patients whose cognitive deficits interfered with their ability to expect relief did not experience it.

Still, looking at the big picture, the effect—call it “placebo” or “meaning” or whatever you like—is pretty powerful. All drugs are tested against it—not because it doesn’t work but precisely because it does. A medication must work five percent better than a placebo to be licensed for use. That makes sense. You certainly would not want to pay $159.95 for a prescription that worked only one percent better than faith that you will get well. The money would be much better spent on a day at the spa.

So... throw out the medications? By no means! They already have been tested and found to be more useful than placebos, or they would not be on the pharmacist’s shelf. But, as Moerman says, the power of expected healing shows that meaning—our interpretation of what is happening to us—can make a huge difference to how effectively medications work. He sums it up: “Meaning can make your immune system work better and it can make your aspirin work better too.” Whether medications are intended to help us with physical or psychological problems, we must actively cooperate with them to make them work their best for us.

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