According to a new study published in the BMJ – formerly the British Medical Journal, U.S. doctors regularly give placebo treatments such as vitamins, sedatives or even antibiotics to patients, even though in many cases these doctors don't expect such treatments to help the patient's underlying disease.

Half of all American doctors responding to a nationwide survey say they regularly prescribe placebos to patients. The study involved 679 internists and rheumatologists chosen randomly from a national list of such doctors. In response to three questions included as part of the larger survey, about half reported recommending placebos regularly. Surveys in Denmark, Israel, Britain, Sweden and New Zealand have found similar results.

Placebo controlled trials are those trials where some participants take a placebo as a control and the others take the drug being investigated. Here the placebo is an inactive substance designed to resemble the drug being tested. It is used as a control to rule out any psychological effects which may show during testing. But the most important thing is the fact that the placebo effect or placebo response is a therapeutic or healing effect of an inert medicine or ineffective therapy, or more generally is the psychosocial aspect of every medical treatment. So it is nevertheless one of the most important factors in our healing.

However the use of placebos is contrary to the recommendation of the American Medical Association, which advises doctors to fully disclose the treatment they are giving their patients. On the other hand some experts make a case for what they call "benevolent deception," or letting a patient believe she's getting a useful treatment because, paradoxically, it might work.

Several studies have found that patients respond positively to placebos upward of 30 percent of the time, though others conclude the effects are minimal.

And the thing is that 41% of doctors used painkillers, 38% used vitamins and 13% used either antibiotics or sedatives. A small but notable proportion of physicians reported using antibiotics and sedatives as placebo treatments during the last year. But the problem is that only rarely do they explicitly describe them as placebos, the authors write.

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

The most common placebos the American doctors reported using were headache pills and vitamins, but a significant number also reported prescribing antibiotics and sedatives. In most cases, doctors who recommended placebos described them to patients as “a medicine not typically used for your condition but might benefit you,” the survey found. Only 5 percent described the treatment to patients as “a placebo.”

The research was paid for by National Institutes Health’s bioethics department and the National Center for Complementary and Alternative Medicine.