In the largest study of its kind, researchers found that having people pray for heart bypass surgery patients had no effect on their recovery. In fact, patients who knew they were being prayed for had a slightly higher rate of complications.
Researchers emphasized that their work can't address whether God exists or answers prayers made on another's behalf. The study can only look for an effect from prayers offered as part of the research, they said.
They also said they had no explanation for the higher complication rate in patients who knew they were being prayed for, in comparison to patients who only knew it was possible prayers were being said for them.
Critics said the question of God's reaction to prayers simply can't be explored by scientific study.
The work, which followed about 1,800 patients at six medical centers, was financed by the Templeton Foundation, which supports research into science and religion. It will appear in the American Heart Journal.
Dr. Herbert Benson of Harvard Medical School and other scientists tested the effect of having three Christian groups pray for particular patients, starting the night before surgery and continuing for two weeks. The volunteers prayed for "a successful surgery with a quick, healthy recovery and no complications" for specific patients, for whom they were given the first name and first initial of the last name.
The patients, meanwhile, were split into three groups of about 600 apiece: those who knew they were being prayed for, those who were prayed for but only knew it was a possibility, and those who weren't prayed for but were told it was a possibility.
The researchers didn't ask patients or their families and friends to alter any plans they had for prayer, saying such a step would have been unethical and impractical.
Dr. Harold G. Koenig, director of the Center for Spirituality, Theology and Health at the Duke University Medical Center, who didn't take part in the study, said the results didn't surprise him.
"There are no scientific grounds to expect a result and there are no real theological grounds to expect a result either," he said. "There is no god in either the Christian, Jewish or Moslem scriptures that can be constrained to the point that they can be predicted."
Within the Christian tradition, God would be expected to be concerned with a person's eternal salvation, he said, and "why would God change his plans for a particular person just because they're in a research study?"
Science, he said, "is not designed to study the supernatural."
