Placebo Effect

Why we need less research on alternative medicine, not more

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By R. BARKER BAUSELL

In 1993 The New England Journal of Medicine published the results of a survey, conducted by David M. Eisenberg and his colleagues, estimating that tens of millions of Americans were frequenting an astonishing variety of bizarre, pseudomedical practitioners. Five years later, The Journal of the American Medical Association published a follow-up survey by the same group, concluding that visits to alternative practitioners were exceeding visits to primary-care physicians in the United States.

Both surveys were heavily cited in the medical literature, extensively covered in the popular media, and used to justify budget increases for the National Institutes of Health's nascent Office of Alternative Medicine and eventually for its successor, the National Center for Complementary and Alternative Medicine.

From a historical perspective, however, there was really nothing newsworthy about the public's infatuation with pseudomedical nonsense. In 1784, for example, Benjamin Franklin, at the behest of the king of France, lent his considerable scientific expertise to a series of experiments that definitively debunked an animal-magnetism therapy then taking Paris by storm.

But while Franklin's experiments may have temporarily inconvenienced the therapy's inventor, Franz Anton Mesmer, they had little lasting effect on his reputation. His name entered our language as a verb — to mesmerize — with no pejorative implications, and he is currently recognized as the father of hypnosis, a therapy used in modern CAM, as complementary and alternative medicine is sometimes known.

Nothing has changed in recent years. In fact, the supplement and herbal industries had become so powerful by 1992 that their supporters were reputed to have sent an estimated two million letters to members of Congress, urging them to prevent the Food and Drug Administration from imposing restrictions on unsubstantiated health claims made on behalf of supplements and herbal products — restrictions that might have prevented the significant loss of life and thousands of adverse effects attributed to the herb ephedra, which was marketed as a weight-loss and athletic-performance supplement before it was finally banned a few years ago.

What is new is the role of reputable institutions in propagating such nonsense: The NIH now awards both research and educational grants in alternative medicine. According to the Web site of the National Center for Complementary and Alternative Medicine, "the immediate goal" of the latter program is "to encourage and support the incorporation of [complementary and alternative medicine] information into medical, dental, nursing, and allied health professional school curricula, into residency training programs, and into continuing education courses. An important longer-term goal [is] to accelerate the integration of CAM and conventional medicine." Many medical schools now work with complementary and alternative clinics, offer fellowships in alternative medicine, and both include material on alternative medicine in required courses and offer optional courses about it.

Fortunately, the National Center for Complementary and Alternative Medicine appears to be considerably more focused on scientific endeavors than its predecessor was, and — in addition to the curricular forays mentioned above — it has provided money for a number of high-quality clinical trials comparing selected alternative therapies to placebos. Not surprisingly, almost all those trials found no difference between the two, but that information has not come cheaply: The NIH has allocated approximately $860-million to the center since the 2000 fiscal year alone.

That leads naturally to a number of questions, including: Did we really need to spend hundreds of millions of dollars on full-fledged randomized and controlled trials to ascertain if thin needles inserted in the body can channel the flow of chi (an energy source as yet undetected by physicists) through a bodily system of meridians (as yet undetected by physiologists) to bring the patient's yin and yang into balance (as yet unmeasured) to ameliorate syndromes (which I doubt even the Chinese really understand) such as wind-damp-hot bi, and thus relieve patients' self-reported symptoms? Wouldn't it be wiser to allocate that money to other NIH agencies whose mission is to try to find an actual cure for a real disease, or to try to find better ways to manage patients' symptoms for those conditions that can't be cured? Or, if that is not politically feasible, in the spirit of transparency shouldn't the alternative-medicine center be renamed the National Center for the Study of Placebo Effects? And should we really keep this nonsense as part of our medical-school curricula?

Scientists, alas, are far less comfortable with multifaceted policy issues than they are with conducting ever-more clinical trials: one therapy for one medical condition at a time. But while that arduous and expensive approach may constitute a perpetual growth industry for both the National Center for Complementary and Alternative Medicine and medical schools, I suspect it would not move us any closer to any scientific conclusions.

And although I would not try to dictate what academics should and should not be allowed to teach, or what they might and might not study, I do believe that alternatives exist to compiling more and more evidence. In conventional scientific practice, the formulation of a plausible biological theory normally precedes its experimental evaluation. That is not possible with complementary and alternative medicine, however, because almost by definition such therapies do not have conventional physiological explanations. Instead they are experimentally evaluated first, and only when someone makes a positive finding — which is extremely rare in well-controlled clinical trials of the therapies — is the plausibility of the underlying theory examined to try to explain why such a result should have occurred.

Of course, a biologist would have little trouble passing judgment on the plausibility of any given complementary or alternative therapy's proposed mechanism of action. And lest anyone think that the acupuncture example above is an anomaly, consider homeopathy, the alternative therapy of choice in France that is also used by many Americans. The theory is that substances that elicit a particular symptom make excellent candidates for treating it — based on the principle of "like cures like" — as long as they are diluted to the extent that not a single molecule of the original substances (e.g., cuttlefish discharge or poison oak) is likely to remain in the solution. The substances, the therapy's advocates insist, retain or increase their effectiveness because the specialized homeopathic dilution process allows the water to "remember" them.

However, a biostatistician or research methodologist would have a much more difficult time synthesizing and evaluating the experimental evidence related to the efficacy of complementary and alternative medicine in general. That is because hundreds of individual therapies are in use, and thousands of trials — almost all methodologically suspect — have been conducted on them, often by advocates of alternative medicine.

Fortunately, impressive resources exist to make evaluation easier. First, we have a clear consensus on what does and does not constitute well-designed and well-executed evaluations of medical efficacy. Second, more than 3,000 high-quality systematic reviews have been completed by the Cochrane Collaboration, a research organization dedicated to locating, appraising, and synthesizing evidence regarding the effectiveness of specific medical interventions of all types, conventional and alternative.

A few years ago, I set out to test the very broad hypothesis that the therapeutic effects attributed to complementary and alternative medicine were basically nothing more than placebo and placebo-like effects. In the latter category, I included such experimental artifacts as natural history, like the fact that many symptoms wax and wane over time, or even resolve themselves completely without intervention; regression-to-the-mean, which can ensure that a symptom will be less severe after even an ineffectual intervention, if the intervention occurred when the symptom was at its worst; and experimental bias, such as failing to conceal from therapists, data collectors, and the participants themselves whether a participant was receiving a placebo or an intervention.

I used this logic: If there is a plausible biological explanation for why the placebo effect should occur, and credible experimental evidence that it does occur; but there is no plausible biological explanation for why any therapeutic effect from complementary or alternative medicine should exist, nor any credible experimental evidence that one does, which cannot also be attributed to the placebo effect; then a reasonable scientific conclusion would be that complementary and alternative therapies are nothing more than placebos.

Analyzing the evidence for the placebo effect, especially with respect to pain relief, was not difficult. We have known for decades, for example, that the mere expectation of relief can trigger the brain's release of endogenous opioids, which in turn cause actual relief. That has been demonstrated repeatedly, with both healthy subjects and patients recovering from surgery. The placebo effect is a most remarkable phenomenon, based on expectations resulting from past experiences and triggered by simple conditioning.

Although the process of evaluating the effectiveness of complementary and alternative therapies was much more arduous, I was able to employ a two-pronged approach that made the task more manageable. First, I looked only at high-quality trials that controlled for the placebo effect, and that had been published since January 2000 in the four American medical journals not limited to a specific disease that had the highest citation rates. Those journals employ more-stringent peer-review systems than other publications, and other criteria I used about sample sizes and attrition rates for subjects ensured the integrity of the results. And second, I examined all the systematic reviews from the Cochrane Collaboration that included two or more trials evaluating the effectiveness of complementary or alternative medicine.

The results were quite revealing. Only one of the trials published in the four selected journals in more than seven years demonstrated an effect of alternative medicine beyond the placebo effect — and that trial was sponsored and conducted, and its publication written, by employees of the company that marketed the product in question. The Cochrane reviews were almost as definitely negative.

Because there is little doubt that a placebo effect does exist, but little evidence to suggest that any complementary or alternative therapy is more effective than a placebo, I believe I have provided a logical answer — supported by empirical evidence — to the question of whether or not we really need to continue spending in excess of $100-million a year on alternative-medicine research to prove the obvious. My conclusion is that sometimes we do actually reach a point at which more research is not needed, and we have reached it with alternative and complementary therapies. Sometimes, in fact, certain types of research need never have been conducted in the first place.

I realize that if even Benjamin Franklin couldn't stem the ever-rising tide of alternative medicine, no one can. I don't even believe that the attempt to do so is a proper role for an educator. Ignorance, along with the Mesmers of the world, will be with us forever. I believe it is enough for us, as educators, to teach our students to recognize (and avoid) the impediments that prevent us from understanding the often complex links between cause and effect.

If nothing else, that topic would prove an appropriate complement to complementary and alternative medicine in our curricula. Perhaps it would even be an antidote.

R. Barker Bausell is a professor of research methodology in the School of Nursing at the University of Maryland at Baltimore, and director of evaluation in its Office of Research. He is author of Snake Oil Science: The Truth About Complementary and Alternative Medicine, published last fall by Oxford University Press.