The New Surprise Effects of Placebo
The human brain is a curious organ. We are continually learning new and very exciting things about this incredibly complicated masterpiece of evolution. But, every now and then, we learn something that shakes to the core our understanding of accepted concepts. This has been the case recently with our understanding of placebos.
Placebos as I’m sure you know, are fake substances, treatments, or procedures that, in and of themselves, have no active ingredient or direct effect. Regardless of the inert nature of placebos, they can and do elicit some powerful responses. This has long been attributed to a person’s beliefs and expectations about the legitimacy of effect. One Japanese study, for example, showed that people who believed they were being exposed to real poison ivy (but were actually exposed to a placebo), developed a painful response that mimicked the actual reaction to legitimate poison ivy (Blakeslee, 1998). In this study, only the subjects’ belief was responsible for the skin rashes. The mind’s powerful capacity, in this case, produced very real and painful responses regardless of the presence of any true irritant.
This is the placebo effect. Again, attribution lies in the person’s beliefs and expectations rather than in the substance, drug, treatment, or procedure. It is important to note that although the beliefs and expectations emanate from one’s mind, the bodily responses can be very real. Scientists use placebos in trials to evaluate treatment efficacy because of this innate gullibility.
The gold standard for evaluation of treatment efficacy (in drug trials) involves double-blinded, randomized, and placebo controlled procedures because, people seem to get better simply from getting attention and/or treatment regardless of form (within limits). This is only true where psychological factors overlay the manifestation of symptoms (Crislip, 2006). Placebos do little to reduce serious medical issues like MS, stroke, or cancer; but people with particularly subjective experiences of pain, affective disorders, and psychologically mediated disorders can and do report improvements when unknowingly taking placebos. Formerly, it was presumed that the patient had to believe that the sugar pill was indeed an actual drug. This presumption is what has been recently questioned. What if the patient knows it is a placebo, will that reduce the treatment efficacy? Recent evidence suggests not!
We must consider a few important things about placebos. The American Medical Association says that “the use of a placebo without the patient’s knowledge may undermine trust, compromise the patient-physician relationship, and result in medical harm to the patient.” Regardless, Kaptchuk et al (2010) noted “a recent national survey of internists and rheumatologists in the US found that while only small numbers of US physicians surreptitiously use inert placebo pills and injections, approximately 50% prescribe medications that they consider to have no specific effect on patients’ conditions and are used solely as placebos (sometimes called “impure placebos”). “Prescribing placebos necessarily involves deception and this brings the practice into question. But deception may no longer be necessary!
Researchers at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston, Massachusetts just published a startling study (Placebos without deception: A randomized controlled trial in irritable bowel syndrome) in the Public Library of Science journal PLoS ONE (Kaptchuk, 2010). And as the title suggests, placebos were knowingly used to evaluate their effectiveness in treating irritable bowel syndrome (IBS). Participants were recruited from advertisements for “a novel mind-body management study of IBS” in newspapers and fliers and from referrals from health care professionals. The authors note that the symptoms of IBS constitute one of the top 10 reasons people seek primary-care treatment.
Eighty, primarily female (70%) subjects with a mean age of 47 years (±18 yrs.), diagnosed with Irritable Bowel Syndrome (IBS), were randomly assigned to one of two groups for a three week trial. One group was an open-label placebo group where the treatment provided was acknowledged to be placebo pills “made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes.” The second group received no-treatment but they did receive the same quality of interaction with health-care providers that the open placebo participants received. Several standardized measures of IBS symptom severity were used.
The subjects knew they were taking inert pills – but the suggestion was made, by the physician, that the pills have resulted in significant improvements in previous clinical trials (which was true and due to placebo effect). As it turns out, the open-label placebo produced significantly higher mean global improvement scores at both the 11-day trial midpoint and at the end of the three week treatment.
Of the participants in the open- or honest-placebo group, 59% experienced adequate relief versus 35% of those in the no treatment group. The authors concluded that “Placebos administered without deception may be an effective treatment for IBS. Further research is warranted in IBS, and perhaps other conditions, to elucidate whether physicians can benefit patients using placebos consistent with informed consent.” The difference between the groups is substantial. Although 35% of the subjects in the no treatment group experienced adequate symptom resolution without any treatment, they were the recipients of some physician attention. Such attention alone is associated with improved outcomes. Further, the 24 point difference is unlikely to be explained by differences in the natural history of the disease (the natural ebb and flow of symptom presentation) or regression toward the mean (the natural tendency for repeated measures to move more closely to the average value) (Crislip, 2006). Because subjects were randomly assigned to the groups, these latter effects are likely to cancel each other out.
So, as it turns out, taking an honest-placebo may substantially reduce IBS symptoms in over half of sufferers. How does this happen? I suggest that because an authority figure suggested that the pill had resulted in significant symptom reduction in previous trials there remains a high probability of the expectancy effect. I question whether it should be considered an “Honest-Placebo.”
So we have the attention provided by the physician, the expectancy affect, and the added ritual of taking the pills. The authors suggest that this latter factor may play an important role in the effect. Regardless, the sugar pill appears to have done something. Perhaps this helps explain why billions of dollars are spent annually on vitamins, “natural remedies,” and homeopathy despite lack of biological plausibility or evidence of treatment efficacy. We are, it seems, inherently gullible people. Placebos work, because the mind is a powerful thing – simply thinking you’re being treated, can make you feel better. Also on the plus side – no long list of scary side effects – although, we could get them, I suppose, if doctors were to imply the possibility.
Blakeslee, S., (1998). Placebos Prove So Powerful Even Experts Are Surprised; New Studies Explore the Brain’s Triumph Over Reality. New York Times 10/13/98. http://www.nytimes.com/1998/10/13/science/placebos-prove-so-powerful-even-experts-are-surprised-new-studies-explore-brain.html?scp=1&sq=poison+ivy+placebo&st=nyt&pagewanted=all
Crislip, M. (2006). QuackCast 5. Placebo Effect. Alt.med effects are often attributed to the placebo effect. .5/22/06
Kaptchuk, T.J., Friedlander, E., Kelley, J. M., Sanchez, M. N., Kokkotou, E., et al. (2010). Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome. PLoS ONE 5(12). http://www.plosone.org/article/info:doi/10.1371/journal.pone.0015591#aff1
Knox, R. (2010). Fake Pills Can Work, Even If Patients Know It. National Public Radio Health Blog. 12/23/10.