Part of the Complementary and Alternative Medicine (CAM) movement is an attempt to insert spirituality into the philosophy and practice of medicine. Most energy healing modalities, for example, have spiritual underpinnings. At the same time there are many attempts to use science to validate the healing power of faith.  This is also an issue that is very attractive to the media, who love articles and headlines about the power of prayer. In our culture – faith sells.

A recent article in the Detroit Free Press is an excellent example of bad reporting and the sensationalizing of this issue. It does a good job of maximally confusing the issue.

To be clear, SBM is not anti-faith or anti-religion. But the issue of faith in medicine raises two main areas of concern. The first is the misrepresentation of the scientific evidence, both for intercessory prayer and the health effects of faith. The second are the ethical and professional implications of mixing faith with medical practice.

Intercessory Prayer

The Detroit Free Press article makes no attempt to distinguish the various issues with faith and medicine, and confuses them together in a misleading way. Intercessory prayer is, essentially, praying for the health of another person. There have been about a dozen such trials with reasonable design. In most the subjects know they may be prayed for. But of course, none of the trials can control for those who are not part of the study praying for a study subject.

Every time such a study shows a hint of positive results the media have a frenzy of reporting that “science proves faith.” When such studies are negative, the footprint in the media is much smaller. What we find when we look at all the studies of intercessory prayer is the type of scatter of results we would expect from a null intervention – one with no effect at all. A 2009 Cochrane review of intercessory prayer studies concluded:

These findings are equivocal and, 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.

These wishy washy conclusions are essentially saying the evidence is negative. The review was also criticized for its methods and discussion of the results – specifically mixing theological and scientific arguments in the discussion and failing to mention significant flaws of the positive studies. But even with these complaints, the results of the review are what we would expect from a treatment effect of zero.

The results of existing research are not sufficient to rule out a small and inconsistent effect – but medical research is never designed to reach such a conclusion, and not being completely disproved is hardly a sufficient reason to endorse a medical intervention.

Again – to be clear – the point of reviewing the evidence is not to argue that individuals should not pray for their loved-ones who are ill. Rather it is important to accurately report the results of the research that has been done – there is no scientific evidence that intercessory prayer is efficacious. Therefore the scientific evidence cannot be used as a justification for inserting religious faith into the practice of medicine.

The Health Effect of Faith

A completely separate question from intercessory prayer is that of the health benefits of having or practicing faith. This is a much more difficult question to assess scientifically. With intercessory prayer there is a specific intervention that can be isolated as a variable. The variable of faith, however, is very difficult to isolate, and most studies barely attempt to do so at all. Most such studies are retrospective and use surveys or questionnaires to gather data, which are plagued by artifacts.

One such study, highlighted in the recent Detroit Free Press article, looked at 88 patients who had suffered Traumatic Brain Injury in the last 10 years. They found a positive correlation between feeling a personal connection with god and having better rehabilitation outcomes. The authors concluded that personal faith “predicts” a good outcome, and the press release (dutifully reprinted by most news outlets) reported that personal faith improves TBI outcomes.

There are two major problems with this study, however. The first is that the survey process itself is likely to bias reporting. If you ask people about their faith (or that of a family member) and then ask them how they are doing, the answer to the one question is likely to influence the answer to the other.

Second – the study found a correlation only, and was not designed to infer any cause and effect. One possible interpretation is that those who were doing better in terms of their recovery from TBI were more likely, as a result, to feel positive about their connection to god.

Much of the research into the question of faith and health is similarly plagued by such flaws, which makes interpreting the research problematic at best.

However, my reading of the literature on this question leads me to conclude that there is a consistent signal in the noise – having a social network consistently positively correlates with better health outcomes. This can be through reduced stress and better practical and emotional support. Humans are social animals, and we simply do better when we are part of a social network than when we are isolated. Religion can provide a useful social network. Faith and religion itself, however, are not the important variable – it’s the social network.

Further, faith both encourages and may result from a positive and hopeful outlook, which can certainly influence the reporting of health outcomes in addition to reducing stress and encouraging better self-care. These variables are rarely controlled for or isolated, however.


The existing research does not support the conclusion that there is any efficacy to intercessory prayer. The research also does not allow for the conclusion that there are health benefits to faith or religion as specific variables. This latter question is open to further research, however.

The scientific evidence can therefore not be used to support the intermingling of faith with the practice of medicine. In any case – doing so raises serious ethical and professional concerns. For example, such practices raise the potential of faith-based discrimination against both physicians and patients. Mixing of faith with medicine can also compromise the professional doctor-patient relationship.

Even if one accepts that there is a health benefit to faith – such a benefit can be entirely realized through private means, without involving the medical profession.

Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.