Over the past several years, there’s been a public argument happening between science and religion on a variety of points. As a physician, I take a non-partisan stance in this debate, and simply want to know what works so that I can best help my patients - as a favorite teacher of mine used to say, ‘There’s no room for dogma in medicine.’ With that in mind, let’s see what happens when religion and science mix directly, in the form of intercessory prayer to achieve health outcomes.
Let’s take a look first at some studies that show positive benefit. One study I came across was done to measure the effect of intercessory prayer on aiding South Korean women undergoing IVF in an effort to become pregnant. 219 women were randomized to either a prayer group or a control group. Interestingly, the women were not informed that they were taking part in a study, nor were their healthcare providers. The prayer groups were located in Canada, Australia and the United States (some distance from South Korea). The study found that the group receiving the prayer intervention achieved implantation and became pregnant at nearly double the rate that their non-prayed-for counterparts did. One of the points this study illustrates is that prayer apparently doesn’t have to happen locally to demonstrate benefit.
A quite large study, done in Israel, was published in the British Medical Journal that looked at 3393 adult patients with bloodstream infections (sepsis). An interesting aspect of this study is that the prayer was done retroactively – 4-10 years after the episodes occurred. This intervention was done on the argument that God was not limited by linear time the way we are, and that we could not assume that time was linear in any event. The study found a minor trend towards decreased mortality among the group receiving prayer, but this was not statistically significant. However, the length of stay in the hospital and duration of fever among the group receiving prayer were both shorter. The duration of fever was mildly shorter among the intervention group, but the length of hospital stay in the intervention group was remarkably shorter, especially as one reached the more severe levels of disease.
One of my favorite studies on this topic was done on bush babies who displayed a condition called chronic self-injurious behavior – a condition characterized by excessive self-grooming that results in the formation of skin lesions, being something like a non-human obsessive-compulsive disorder. Twenty-two bush babies were assigned to receive either l-tryptophan alone, or l-tryptophan and intercessory prayer for four weeks. After the four weeks, researchers found that the bush babies receiving prayer in addition to conventional treatment had a reduction in wound size compared to their counterparts, engaged in less wound-grooming, and less grooming behaviors overall. The authors noted that because the study was done on non-human animals, the results were not susceptible to the effects of placebo, as they might have been in a human trial.
Here's a pic of Otolemur garnetii, the type of bush baby studied
Obviously, however, not all studies have shown benefit. A study done among kidney dialysis patients showed that intercessory prayer could not be distinguished from the effect of expectancy (sometimes called ‘placebo’) in improving medical or psychological measures of patient’s well-being, and a study of HIV patients that included intervention by professional healers, untrained nurses, or no intervention found that there was no benefit to prayer among study participants, and no clinical outcome could be attributed to the prayer. We shouldn’t be surprised that some studies have shown no benefit, as almost all treatments have tested poorly at one point or another.
One interesting focus of study has been on cardiac patients in the hospital. A study was published in 1999 in the Archives of Internal Medicine which suggested that intercessory prayer might improve a patient’s experience in the coronary care unit. In the study, 990 patients were randomized into intervention or placebo groups without their knowledge, and either did or did not receive intercessory prayer while they were in the hospital. While the length of CCU and hospital stay did not vary between groups, the patients in the prayer group had lower CCU course scores, which basically means that they had fewer adverse events in the course of their stay. However, a year later, the Mayo Clinic published a similar study which found no significant benefit from intercessory prayer among 799 CCU patients.
These findings caught the eye of researchers at Harvard’s Medical School, and so they set up a similar study with one twist – that along with the patients who were blinded as to whether or not they would receive prayer, a third arm of patients would be told they would be receiving prayer, and did receive prayer. This study was the largest of all, with a total of 1802 patients being involved. However, not only did this study find that prayer did not reduce complications in patients receiving CABG (commonly known as bypass surgery), nor did it change mortality after surgery, but in fact, being certain that one was receiving prayer was associated with a higher incidence of complications. The study authors brushed off this as a fluke, but needless to say, this was not good news. In reaction to the published results, commentators noted that participants’ concealing from their providers the fact that they were being prayed for may have caused this increase in complications. This study is confusing at best, troubling at worst, and needs further examination, as the commentators called for.
What happens when we put this all together? A Cochrane Systematic Review looked at 10 studies on intercessory prayer for patients already receiving routine care for a variety of conditions. Not unexpectedly, the review noted that the results were mixed, and that although some studies showed positive results, others showed no result. The review declared that there was not enough data to recommend either in favor or against of the use of prayer to improve health. The authors went on to say that resources available for the study of prayer should be better devoted to other questions in health care. The Cochrane Review is a very high quality, but largely scientifically conservative organization, and their commentary is unsurprising.
So what’s my opinion after reading all of this literature? I think you ought to pray if the spirit moves you. A few studies have noted beneficial effects. A few have noted no measurable effect. I think that the one outlier study, which showed a negative effect needs a critical reexamination – the authors brushed off the negative effect, but I think it’s worth taking a good hard look and trying to determine what factors may have caused the negative effect (I’m inclined to believe that the stress of concealing information from one’s providers while undergoing major surgery may have been part of the cause). In the future, research into this topic should be improved – a few studies have noted a measurable beneficial effect, and I think we need to nail down factors that influenced that positive effect, a process that will require further quantifying and describing the prayer process. I have no illusions that this will remain on the back burner for researchers, and some might argue that quantifying prayer defeats the whole point, but I think that there’s enough evidence that something is going on that we should work to figure it out.