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A 'little bombshell of a study' on the placebo effect raises provocative questions

Science writer Steve Silberman has written a terrific background article on the “little bombshell of a study” on placebos that was published right before Christmas in the open-access medical journal PLoS One.

The study, writes Silberman, “threatens to make humble sugar pills something they’ve rarely had a chance to be in the history of medicine: a respectable, ethically sound treatment for disease that has been vetted in controlled trials.”

And indeed it does. Here’s Silberman’s summary of the study:

[A] group of leading placebo researchers [including Irving Kirsch at the University of Hull in England and Ted Kaptchuk at Harvard] … tracked the health of 80 volunteers with irritable bowel syndrome for three weeks as half of them took placebos and the other half didn’t. A painful, chronic gastrointestinal condition, IBS is serious business. It’s one of the top ten reasons why people seek medical care worldwide, accounting for millions of dollars a year in health care expenditures and lost work-hours.
In a previous study published in the British Medical Journal in 2008, Kaptchuk and Kirsch demonstrated that placebo treatment can be highly effective for alleviating the symptoms of IBS. This time, however, instead of the trial being “blinded,” it was “open.” That is, the volunteers in the placebo group knew that they were getting only inert pills — which they were instructed to take religiously, twice a day. They were also informed that, just as Ivan Pavlov trained his dogs to drool at the sound of a bell, the body could be trained to activate its own built-in healing network by the act of swallowing a pill.
In other words, in addition to the bogus medication, the volunteers were given a true story — the story of the placebo effect. They also received the care and attention of clinicians, which have been found in many other studies to be crucial for eliciting placebo effects. The combination of the story and a supportive clinical environment were enough to prevail over the knowledge that there was really nothing in the pills. People in the placebo arm of the trial got better — clinically, measurably, significantly better — on standard scales of symptom severity and overall quality of life. In fact, the volunteers in the placebo group experienced improvement comparable to patients taking a drug called alosetron, the standard of care for IBS.

Silberman’s article includes a long and provocative Q&A with Kirsch, whose 2010 book, “The Emperor’s New Drugs,” caused an uproar in many medical circles with its claim that the placebo effect may be entirely responsible for the therapeutic benefits of antidepressant drugs.

On the topic of antidepressant therapy, Kirsch had this to say to Silberman:

The more I learn, the more convinced I become that the benefits of drugs for depression are not biologically driven, but driven by the placebo effect. The thing that convinces me most is that nearly all drugs for depression — despite having very different chemical compositions — are of equal benefit. In other words, you have drugs that are completely different in what they do chemically — even drugs that operate by opposing mechanisms — creating the same level of effect.
The most commonly employed antidepressants are supposed to increase the amount of serotonin in synapses in the brain, but there are also antidepressants that decrease the level of serotonin in the brain, and they both have the same effect therapeutically. The effects of these drugs seem to be completely independent of their chemical composition.

Kirsch was equally blunt about the role of the placebo effect in alternative and complementary medicine:

I think the effects of acupuncture are largely placebo effects, if not entirely. It’s a very good placebo effect; a really healthy and large placebo effect. The last study we did on IBS was with placebo acupuncture — sham acupuncture. Sham acupuncture does as much good as real acupuncture. You can do it without needles and still get the same effect. Practitioners of acupuncture, homeopathy, and other alternative and complementary medicines do an excellent job of eliciting and bolstering placebo effects.
We know from our research the things that make a difference: how much time you spend with a patient, how supportive and empathic you are, how well you listen, and how confident you are in being able to help. Complementary and alternative medicine practitioners are particularly good at these things. These are obviously things that physicians can do as well, and some are very good at eliciting placebo effects. But those qualities are becoming more rare in conventional medical practice.

Silberman’s article is long, but well worth the read. You’ll find it at his NeuroTribes blog here. He wrote another award-winning article on the placebo effect for Wired last year, which you can read here.

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Comments (1)

Very interesting stuff!