Debunking the power of the placebo effect.
In a famous 1955 monograph in the Journal of the American Medical Association, Henry Beecher coined the term "powerful placebo." He used it to describe the miraculous improvement he said was seen in patients who thought they were getting medicine but really weren't. Beecher went so far as to say that this placebo effect accounted for precisely 35.2 percent of a treatment's results. And so he popularized the notion that patients could spontaneously heal—not only from psychological distress, but from physical disease—if they simply believed they were getting treatment.
Beecher's paper lay the foundation for the modern clinical trial, in which half of subjects take placebo pills or, sometimes, undergo sham procedures to fool them into thinking they are getting real treatment. Without this ritual, the thinking goes, the trials' outcomes would be skewed by the power of suggestion. In other words, scientists must give trial subjects placebos to distinguish the effect of taking active medication from the effect of taking a pill that you think will make you better, because you don't know it's only sugar.
Beecher's paper is highly suspect. Half the studies he cited were his own, and his math was, frankly, misleading. Ted Kaptchuk, an associate professor at Harvard Medical School and former FDA expert panelist, dismisses the paper as a "polemical ploy," and other researchers have derided Beecher as "statistically naïve to the extreme." And yet Beecher's paper and the notion of a powerful placebo effect have escaped widespread scrutiny. For decades, mainstream medicine has uncritically promoted faith in the placebo effect—leaving behind reality-based science in the process.
As a result, some clinical trials go to extraordinary lengths to minimize the chances that positive thinking can cure all manner of illness and thus bias results. Consider the experience of George Doeschner, a New York electrician with Parkinson's disease, a condition caused by nerve degeneration in the midbrain. Doeschner flew to the University of Colorado in 1996, when he was 53, to enroll in an experiment to inject brain tissue salvaged from human fetuses into patients' brains, in hopes the cells would take up residence and restore neural function. Twenty patients would get the fetal cells; another 20 would just be a comparison group, receiving no treatment. But the researchers worried: If the injection group recovered, would that be because of the fetal cells pumping out dopamine, or was it possible that a patient's belief that the injections helped could explain his recovery of midbrain function? So, with the patients' consent, measures were taken to make them all think that they were getting treatment, even if they weren't.
On the day of his procedure, Doeschner was wheeled into the operating room and underwent an MRI scan to guide the neurosurgeon. Under local anesthesia—while he remained awake—the surgeon drilled four holes in his skull to expose the dura, or outmost membrane of the brain, for the fetal-cell injection. Then the surgeon stood outside Doeschner's field of view and did … nothing. Doeschner returned to the recovery room, having undergone a "sham surgery." Like all the subjects, he didn't find out for a year whether he'd really gotten the cells. (In the end, there was minimal difference in medical outcome between the treatment and sham group.) Fears of a strong placebo effect in this field were so strong that, according to lead researcher Dr. Curt Freed, the National Institutes of Health rejected a competing Yale Medical School study of fetal-cell injection because it lacked a sham-surgery group.
There are other similar trials: In the late 1990s, veterans enrolled in a Houston study of knee arthritis were assigned randomly to have either real knee surgery or a sham procedure, which consisted of being sedated, getting prepped in the operating room, having four superficial knee incisions, and hearing simulated splashing sounds. In 2005, 74 migraine sufferers in England had experimental devices snaked through a vein (subscription required) in their groin and implanted into the heart; 73 people in a sham group got the groin incisions without the device. More commonly, though, placebo trials involve dummy medication. Since 1962, the Food and Drug Administration has required all new drug approval trials—like those for high cholesterol, AIDS, cancer, and depression—to include a placebo group, where half the patients get inactive pills to create the false impression of therapy.
Darshak Sanghavi is Slate's health care columnist. He is chief of pediatric cardiology and associate professor of pediatrics at the University of Massachusetts Medical School as well as the author of A Map of the Child: A Pediatrician's Tour of the Body. Follow him on Twitter.
Photograph of pills by Ryan McVay/Photodisc.