A large study now shows no increase in the health of patients being prayed for.© Punchstock

Distant prayers do not help people recovering from heart surgery and could even cause them more health problems, according to the results of a large and controversial clinical trial that critics have labelled a waste of money.

Many people believe that prayers sent by a group of strangers, so-called intercessory prayer, can help a sick patient. This idea has been tested in a handful of studies before. But the results have been unclear and the subject highly contentious, in part because the methods may have been faulty and the numbers of people involved small.

The new study is the largest and most rigorous to put the power of distant prayer to the test, using similar protocols to those used in clinical trials of new drugs.

The team recruited patients who were about to undergo coronary bypass surgery at six US hospitals. They randomly assigned them to one of three groups: about 600 were told that they might be prayed for but were not; 600 were told that they might be prayed for and were; and another 600 were prayed for and knew about it.

Extra anxiety

Each night of the trial, the team faxed a list of the patients to be prayed for to three Christian groups, whose members prayed for successful surgery and a quick recovery. Each of these patients was on the prayer list for two weeks. The doctors then monitored all the patients for medical complications in the 30 days following surgery.

The investigators found that praying made no difference to the health of patients who didn't know whether they were being prayed for or not. But the group who knew that they were being prayed for was approximately 14% more at risk of complications, mainly abnormal heart rhythms. Perhaps, the investigators suggest, this was because it made them more anxious.

The study, which was funded by the John Templeton Foundation, an organization that sponsors research examining science and religion, is published in the American Heart Journal¹.

Test of faith

At least some researchers think that the trial, which cost US$2.4 million, was a colossal waste of time and money. "We don't need studies like this," says behavioural scientist Richard Sloan, an authority on prayer and medicine at Columbia University in New York City.

Prayer is highly valued by many people, says Sloan, and there is no need for scientists to empirically prove whether or not it works. "It's demeaning of the religious experience."

Jeffrey Dusek of Harvard Medical School in Boston, Massachusetts, defends the decision to carry out the study: "We felt it was an opportunity to really provide scientific rigour to this area of research," he says. But now this study is done, it is open to question whether this avenue of research should continue, he says.

Psychiatrist Jon Streltzer, an expert in psychosomatic medicine at The University of Hawaii at Honolulu says that scientists can ask more useful and measurable questions about the impact of religion on health, such as whether a patient's beliefs can boost their own health, or whether the prayers and concern of close relatives can help. "I don't think that science can study supernatural phenomena," he says.

"The psychological aspects deserve further study," Dusek adds.

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• References

  1. Benson H., et al. Am. Heart J., 151. 934 - 942 (2005).