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Study highlights difficulty of isolating effect of prayer on patients

By Staff writer of The Christian Science Monitor / April 3, 2006



The results of a long-awaited scientific study aimed at measuring the effect of third-party prayer for hospitalized patients not only did not match the expectations of those conducting the study, but also may have raised more questions for researchers than it answered. Among them: Can even the most carefully designed trial measure prayer's effects?

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The Study of the Therapeutic Effects of Intercessory Prayer (STEP), published online March 30 by the American Heart Journal, showed no positive effect from the use of third-party intercessory prayer on behalf of patients undergoing a specific type of heart surgery at six medical centers around the United States when compared with a control group who were not prayed for as part of the study.

Another unexpected result: Patients who knew they were being prayed for had somewhat more medical complications than another group who also had received prayer but were uncertain as to whether they had or not. Researchers had expected the reverse outcome.

STEP aimed to provide more accurate results than four previous trials that involved cardiac patients, the authors said. The results of those trials were mixed: Two found a beneficial effect of prayer; two found no benefit. The earlier studies were also criticized for having design flaws, the authors said.

But the study itself is unlikely to satisfy those who question whether the effects of prayer can be measured using conventional scientific testing. They ask: How do you define what constitutes a prayer? Are all forms of prayer equally effective? How do you design a "dose" of prayer that is the same for each patient? And how do you rule out the effects of the patients' own prayers or prayers from others not involved in the study on behalf of the patient?

About 95 percent of all the STEP participants - including a control group that was not prayed for as part of the study - said that they expected friends, relatives, or members of their religious institutions to be praying for them. About two-thirds strongly agreed with the statement, "I believe in spiritual healing."

The authors were careful to point out the limited conclusions that could be drawn from their study. "Private or family prayer is widely believed to influence recovery from illness, and the results of this study do not challenge this belief," the authors wrote. "Our study focused only on intercessory prayer as provided in this trial and was never intended to and cannot address a large number of religious questions, such as whether God exists, whether God answers intercessory prayers, or whether prayers from one religious group work in the same way as prayers from other groups."

For some involved in exploring the issues of spirituality and health, the new study only confirms their reservations. "Scientific studies are just not capable of showing that prayer works," says Dr. Harold Koenig, an associate professor of medicine and co-director of the Center for Spirituality, Theology, and Health at Duke University's Medical Center.

"I think that prayer absolutely does work and that God answers prayer and that we can continue to pray for our loved ones," Dr. Koenig says. "We should not think that science can answer every question there is."

How the study was designed

The authors of STEP wanted to study the effect of intercessory prayer and whether knowledge that the patient was receiving prayer made a difference. In the study, 1,802 cardiac patients awaiting surgery at six medical centers were divided evenly and randomly into three groups. All the patients were told that they were involved in a clinical trial and gave their permission. Those in Group 1 received intercessory prayer after being told that they may or may not receive prayer. Those in Group 2 did not receive prayer after being told that they may or may not receive prayer (the placebo, or control, group). Group 3 received prayer after being told it would receive prayer.

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