More than half of American doctors prescribe placebos to make their patients feel better, according to a nationwide survey published Oct. 24 in the online edition of the British Medical Journal.

Scientists have long known of the “placebo effect” in which patients given a fake treatment often improve anyway simply because they expected to get better.

The survey was addressed to 1,200 internists and rheumatologists but only 679 responded. The participants were addressed a series of questions: 1. If a clinical trial showed a sugar pill was better than no treatment for fibromyalgia, would you recommend sugar pills to fibromyalgia patients? Fifty-eight percent of doctors responded affirmative. 2. Do you ever actually recommend treatments primarily to enhance a patient's expectations? Eighty percent of doctors said yes. 3. In the last year, did you recommend a placebo treatment to a patient? Fifty-five percent of doctors said yes.

“Prescribing placebo treatments seems to be common and is viewed as ethically permissible among the surveyed U.S. internists and rheumatologists,” the survey concludes.

The placebo pills - usually vitamins, over-the-counter painkillers, sedatives and antibiotics - didn’t actually treat the condition for which they were prescribed. Forty-one percent of doctors responding the survey used over-the-counter painkillers as placebos, 38 percent used vitamins, 13 percent used antibiotics and 13 percent used sedatives.

Surveys in Denmark, Israel, Britain, Sweden and New Zealand had similar results.

The bad part is that most doctors are not honest with their patients about what they are doing, the survey found. Only five percent said they tell patients explicitly that they are prescribing placebo pills. On the other hand, most doctors recommending placebos describe them to patients as “a medicine not typically used for your condition but might benefit you.” This practice contradicts advice from the American Medical Association, which recommends doctors use treatments with the full knowledge of their patients.

“It’s a disturbing finding. There is an element of deception here which is contrary to the principle of informed consent,” said Franklin G. Miller, director of the research ethics program at the U.S. National Institutes Health and one of the study authors.

“It's a gray zone. It is not ethical to actively deceive patients. But when doctors give something which they think will help but don't think it helpful to explain the full reasoning about why it will help, that's a gray zone,” said Dr. Farr A. Curlin, an assistant professor of medicine at the University of Chicago, and a member of the team reporting the findings of the survey.

The American Medical Association clearly says that 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. Physicians may use placebos for diagnosis or treatment only if the patient is informed of and agrees to its use, the organization further requires.