About half of American doctors in a new survey say they regularly give patients placebo treatments — usually drugs or vitamins that won't really help their condition.

And many of these doctors are not honest with their patients about what they are doing, the survey found.

That contradicts advice from the American Medical Association, which recommends doctors use treatments with the full knowledge of their patients.

"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 study was being published online in Friday's issue of BMJ, formerly the British Medical Journal.

Placebos as defined in the survey went beyond the typical sugar pill commonly used in medical studies. A placebo was any treatment that wouldn't necessarily help the patient.

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

Doctors under pressure

"Doctors may be under a lot of pressure to help their patients, but this is not an acceptable shortcut," said Irving Kirsch, a professor of psychology at the University of Hull in Britain who has studied the use of placebos.

Researchers at the NIH sent surveys to a random sample of 1,200 internists and rheumatologists — doctors who treat arthritis and other joint problems. They received 679 responses. Of those doctors, 62 per cent believed that using a placebo treatment was ethically acceptable.

Half the doctors reported using placebos several times a month, nearly 70 per cent of those described the treatment to their patients as "a potentially beneficial medicine not typically used for your condition." Only five per cent of doctors explicitly called it a placebo treatment.

Most doctors used actual medicines as a placebo treatment: 41 per cent used painkillers, 38 per cent used vitamins, 13 per cent used antibiotics, 13 per cent used sedatives, three per cent used saline injections, and two per cent used sugar pills.

In the survey, doctors were asked if they would recommend a sugar pill for patients with chronic pain if it had been shown to be more effective than no treatment. Nearly 60 per cent said they would.

Smaller studies done elsewhere, including Britain, Denmark and Sweden, have found similar results.

Jon Tilburt, the lead author of the U.S. study, who is with NIH's bioethics department, said he believes the doctors surveyed were representative of internists and rheumatologists across the U.S. No statistical work was done to establish whether the survey results would apply to other medical specialists, such as pediatricians or surgeons.

The research was paid for by NIH's bioethics department and the National Center for Complementary and Alternative Medicine.

'Something is better than nothing'

The authors said most doctors probably reasoned that doing something was better than doing nothing.

In some cases, placebos were given to patients with conditions such as chronic fatigue syndrome. Doctors also gave antibiotics to patients with viral bronchitis, knowing full well that a virus is impervious to antibiotics, which fight bacteria. Experts believe overuse of antibiotics promotes the development of drug-resistant strains of bacteria.

Some doctors believe placebos are a good treatment in certain situations, as long as patients are told what they are being given. Dr. Walter Brown, a professor of psychiatry at Brown and Tufts universities, said people with insomnia, depression or high blood pressure often respond well to placebo treatments.

"You could tell those patients that this is something that doesn't have any medicine in it but has been shown to work in people with your condition," he suggested.

However, experts don't know if the placebo effect would be undermined if patients were explicitly told they were getting a dummy pill.

Brown said that while he hasn't prescribed sugar pills, he has given people with anxiety problems pills that had extremely low doses of medication. "The dose was so low that whatever effect the patients were getting was probably a placebo effect," he said.

Kirsch, the psychologist, said it might be possible to get the psychological impact without using a fake pill. "If doctors just spent more time with their patients so they felt more reassured, that might help," he said.

Some patients who had just seen their doctors at a clinic in London said the truth was paramount.

"I would feel very cheated if I was given a placebo," said Ruth Schachter, an 86-year-old Londoner with skin cancer. "I like to have my eyes wide open, even if it's bad news. If I'm given something without being warned what it is, I certainly would not trust the doctor again."