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When it comes to the placebo effect, context is everything

The placebo phenomenon is very real.

But it’s how a placebo is administered — the entire “psychological context” of receiving it — and not just the “dummy” pill (or treatment) itself, that makes the placebo effect work, according to a new, large review of placebo studies.

The strongest factor behind the placebo’s effectiveness is the patient’s expectation that the sham treatment or procedure will help them, say the authors of the review, which appears in the Feb. 20 issue of the medical journal The Lancet.

And that expectation is greatly enhanced by the bedside manner of the physician.

The reviewers cite, for example, a 2008 study that divided 262 people with irritable bowel syndrome into three treatment groups: One group received no treatment. Another received a placebo acupuncture treatment from practitioners who were told to interact only minimally with the patients. And the third received placebo acupuncture from practitioners who were instructed to convey “warmth, attention, and confidence” to their patients. (Acupuncture was chosen because it’s been shown to have a strong placebo effect.)

After three weeks, the percentage of patients who said they felt better was 28 percent for the no-treatment group, 44 percent for the “limited-interaction-with-practitioner” group, and 62 percent for the group that received the warm-and-fuzzy attention of their acupuncturist.

Other research described in the review has found that the placebo effect can play an important part in the effectiveness of active drugs. This has been demonstrated in clinical trials with “open-hidden” designs — studies in which one group of patients receives, say, an injection of an active drug directly from a physician while a second group receives it “silently” from a computerized delivery device, and at a point and time unknown to the patient.

Drugs delivered by hidden methods are less effective, studies have found.

Could the placebo effect, therefore, be what’s behind some or even all of the therapeutic effects of real drugs?

Maybe, suggest the review’s authors. “Placebo mechanisms can interact with drug treatments, even if no placebo is given, since every treatment is given in a therapeutic context that has potential to activate and modulate placebo mechanisms,” they write.

The reviewers point out that the painkiller proglumide was found to be more effective than placebo in a standard randomized clinical trial, but not when it was administered secretly, without patients’ awareness.

Provocatively, the authors suggest that the medical community should explore the possibility of using the placebo effect as treatment in certain circumstances.

That would require your physician to practice deception — a matter that, of course, raises significant ethical issues.

For more extended summaries of the review, including a discussion of the ethical dilemma the placebo effect presents to physicians, go here and here. And for an excellent audio explanation of the placebo effect, check out physician-journalist Ben Goldacre’s short video here.

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Comments (1)

  1. Submitted by Rod Loper on 02/23/2010 - 01:59 pm.

    Thank you for this great post. A related topic would be one on the consequences of massive drug advertising on television on the placebo effect
    (not to mention its increasing health care inflation.

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