That’s just a sample of the headlines accompanying a new study on placebos published in PLoS ONE. The study attempts to nail down some questions about the placebo effect, especially regarding how to harness it ethically, without deception. The placebo effect, a medical improvement not due to a biologically active treatment, is a difficult concept. Some of it is stochastic or artifactual, that is, any time you study human beings, it is possible to measure statistical “improvement” that may not have real clinical meaning. The other part of placebo is the response to being cared for independent of other biological interventions. Journalist Steve Silberman (with whom I have disagreed about placebo in the past, and I’m still not sure who’s right) quotes anthropologist Dan Moerman (emphasis mine):
“I was really surprised at how well the non-placebo group did,” Moerman says in email. “Note I don’t call them a ‘no treatment group’ because they, and everyone else, received exemplary treatment here: they were listened to, examined, encouraged, supported. They were able to talk with, and be taken seriously by, people who understood their issues, things they probably had serious difficulty discussing with their own families. I think it likely that the effectiveness of the placebos above and beyond all the other treatment would have been diminished without the whole system of compassionate care.”
So the non-artifactual part of placebo isn’t really “no treatment”, it is less tangible treatment. In the current study, this distinction becomes important. There are really two types of placebo: the kind used as a “dummy” treatment in placebo-controlled trials, and the placebo effect observed when we treat people well. In attempting to harness placebo as an actual treatment, we run into a number of problems. The first is teasing out what we mean by “placebo”, the second the ethics of deceiving patients. The current study by Kaptchuck, et al attempts to tease out the second question in order to answer the first.
They chose to study irritable bowel syndrome (IBS), an common, unpleasant disorder of unknown cause. It is often exacerbated by stress and anxiety, and the natural course of the syndrome and of its attacks is to come and go spontaneously. This fact itself makes studying interventions difficult, as it is harder to decide whether a treatment worked, or the patient simply got better as they would have. Since IBS is often made worse with stress, it is also possible that simply comforting a patient may improve the symptoms. Can this comfort be labelled “placebo” simply because it is non-pharmacologic?
All of this points to the difficulty of defining what a “placebo treatment” actually might be. Giving comfort and care is active treatment. The current study did not compare “placebo” to no treatment as they claim, but an active intervention, albeit one that was non-pharmacologic:
The provider clearly explained that the placebo pill was an inactive (i.e., “inert”) substance like a sugar pill that contained no medication and then explained in an approximately fifteen minute a priori script the following “four discussion points:” 1) the placebo effect is powerful, 2) the body can automatically respond to taking placebo pills like Pavlov’s dogs who salivated when they heard a bell, 3) a positive attitude helps but is not necessary, and 4) taking the pills faithfully is critical.
Both groups were treated “in the context of a warm supportive patient-practitioner relationship,” but the subjects were essentially told that the pills would work, negating any real claim that this is a “placebo without deception.”
This study simply shows what we already know: treating patients well helps them. All the rest is commentary; don’t bother to go and learn it.
Kaptchuk, T., Friedlander, E., Kelley, J., Sanchez, M., Kokkotou, E., Singer, J., Kowalczykowski, M., Miller, F., Kirsch, I., & Lembo, A. (2010). Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome PLoS ONE, 5 (12) DOI: 10.1371/journal.pone.0015591
Two other excellent discussions online:
Ed Yong at NERS
Orac at Respectful Insolence