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Home » Intercessory prayer in medicine — systematic reviews say it does not work

Intercessory prayer in medicine — systematic reviews say it does not work

Intercessory prayer, where people pray for the health of someone in a hospital, has been studied for a while to determine whether it is effective. I keep reading that people believe it has been “proven” to work, but I have always been skeptical.

I didn’t realize that there are published studies about intercessory prayer, but I shouldn’t be surprised. There are even systematic reviews that examined the body of research — spoiler alert, there isn’t much evidence that it works.

If intercessory prayer works, I would want to rely upon that famous Carl Sagan quote — “extraordinary claims require extraordinary evidence.” The indisputable medical evidence supports real medicine, not prayers. The prayer supporters haven’t even been able to provide ordinary evidence.

So let’s take a look at some of the science supporting or refuting the effectiveness of intercessory prayer.

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The pseudoscience of intercessory prayer

Let’s start with an important premise of any study of intercessory prayer — you cannot do a double-blind clinical trial to compare the effectiveness of prayer versus a placebo. It would be highly unethical to withhold standard medical treatment for any disease, like cancer. So, the best one can do with a clinical study is to compare the outcomes of two groups, both receiving standard treatment. One group would receive prayer and the other group wouldn’t.

That being said, let’s take a look at some of the best research into prayer in medicine.

The American Cancer Society’s article on Faith Healing pretty much debunks it:

One review published in 1998 looked at 172 cases of deaths among children treated by faith healing instead of conventional methods. These researchers estimated that if conventional treatment had been given, the survival rate for most of these children would have been more than 90 percent, with the remainder of the children also having a good chance of survival. A more recent study found that more than 200 children had died of treatable illnesses in the United States over the past thirty years because their parents relied on spiritual healing rather than conventional medical treatment.

The studies that are included in this statement include, of course, faith healing, where only prayer is used to treat illness. Children died because of this.

So, let’s look more at intercessory prayer as an adjunct to standard medical treatments. A

In a systematic review (considered the pinnacle of biomedical research) published in the Cochrane Database of Systematic Reviews, Cochrane concluded after reviewing 10 studies that:

…although some of the results of individual studies suggest a positive effect of intercessory prayer,the majority do not and the evidence does not support a recommendation either in favour or against the use of intercessory prayer. We are not convinced that further trials of this intervention should be undertaken and would prefer to see any resources available for such a trial used to investigate other questions in health care.

That is about as weasel-worded of a statement as you can find. Steven Novella at Science-Based Medicine ripped this study as being “wishy-washy”, meaning the conclusions are not strong enough.  And they’re not.

Some of the studies compared patients who received standard care, but with and without the addition of intercessory prayer. For a study to have validity, it also needs to be blinded, that is, neither the patients nor the observers should know who was in which wing, at least until the study is complete and analyzed. Not all of these studies are so designed.

Some of the included studies claim to have found positive effects for intercessory prayer (and at least one that found negative effects), but these studies mostly have identified procedural flaws.

Another systematic review, published in the Annals of Behavioral Medicine, concluded:

There is no scientifically discernable effect for IP (intercessory prayer) as assessed in controlled studies. Given that the IP literature lacks a theoretical or theological base and has failed to produce significant findings in controlled trials, we recommend that further resources not be allocated to this line of research.

The science-speak of the authors was pretty clear — don’t waste money studying the effect of intercessory prayer, because not only is it difficult to analyze it also has shown no effect.

A third systematic review, published in the Annals of Internal Medicine, concluded that:

The methodologic limitations of several studies make it difficult to draw definitive conclusions about the efficacy of distant healing. However, given that approximately 57% of trials showed a positive treatment effect, the evidence thus far merits further study.

This is a typical science-speak that says that there is no evidence that intercessory prayer works, but because poorly designed studies may show a positive effect, we should examine it further. However, in science, you either have evidence to support a hypothesis or you don’t. Weak evidence is not enough, especially when you’re discussing the health of a patient.

Furthermore, if the patient is aware of someone praying for them, there might be positive results. But this is why we double-blind clinical trials because if you know something is being done for you, the placebo effect takes over.

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It’s clear to me there is no clarity. But if I stand by the statement, “extraordinary claims require extraordinary evidence,” the lack of clear results means there is no extraordinary evidence. There’s not even ordinary evidence.

At best, we see a placebo effect. At worst, it’s pure pseudoscience.

I know that there will be anecdotes that will try to convince you that intercessory prayer works. Someone prayed for a cancer patient and they miraculously went into remission. Of course, this often ignores the power of medicine itself to treat that cancer — but the advocates of prayer will claim it worked, while the oncologist will roll his eyes and know it was surgery or chemotherapy doing its job.

There is no harm in prayer unless people think it’s a replacement for science-based medicine. But it’s probably not doing anything at all.


Michael Simpson

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