Does Spiritual Life Reduce Substance Abuse?

A Major Advance in Our Knowledge about Religion and Health

While there have been many prior studies on spirituality and health and even many meta-analyses within the religion and health literature, most of these are relatively weak in design, employing cross-sectional data, collected only at one time point, which makes it difficult to determine what causes what. Does religious service attendance protect against smoking, or do those who smoke feel less comfortable attending religious services? To make these determinations, we need longitudinal data, gathered over time, though even with such data, we can only approach genuine knowledge about causation when the accumulated evidence, generally from multiple studies, is sufficiently strong and unambiguous to render any alternatives untenable. And as we’ve noted previously, achieving genuine knowledge about causal claims is also difficult because of the possibility that researchers are neglecting some additional “confounding” factor that explains the apparently causal relationship, or because of statistical uncertainty, or questions of generalizability, or biases that can creep into the research process.

One approach to trying to address these challenges is meta-analysis, or the synthesis of previous studies on a particular topic. This still doesn’t solve all the issues since the results of such a synthesis are only as good as the quality of the studies that go into it. However, by restricting to the most rigorous studies—large, longitudinal in design, and with good control for confounding—one can begin to move towards stronger evidence. That is precisely what we did in our most recent study published in JAMA Psychiatry on the potential effects of religion and spirituality on substance use and abuse.

Despite a very large literature in religion and health, to the best of our knowledge, there have only been two prior meta-analyses restricted to longitudinal studies: one on religiosity’s effects on all-cause mortality in 2009, and one on mental health in 2021. Both found important protective effects. Such meta-analyses of longitudinal studies constitute substantial undertakings and have only been occurring in the religion and health literature about once per decade.

With generous support from the Templeton Religion Trust and the Lee Family Fund, our most recent study from the Human Flourishing Program at Harvard and the Initiative on Health, Spirituality, and Religion, led by our colleague Dr. Howard Koh, has extended such approaches yet further to examine the relationship between religion and spirituality with substance use and abuse. We drew upon a prior major review we had published in JAMA of the most rigorous 21st-century studies from 2000-2022, which were longitudinal in design and had sample sizes of at least 1000, or were randomized trials. We then synthesized the evidence from the 55 studies that met these criteria for their rigorous design.

What We Found

Overall, we found that among these various studies, spiritual or religious participation was associated with a 13 percent reduction over time in hazardous alcohol and other drug use. The strength of the effects seemed relatively similar across the different substances examined, namely alcohol, tobacco, marijuana, and illicit drugs. There was certainly variation across studies and populations, but the majority indicated a reasonably large protective effect. There was some variation across different types of spiritual practices, with participation in religious communities (weekly service attendance) having the largest effect, with an 18 percent reduction in hazardous substance use on average. There was perhaps slight evidence that the effects of religious and spiritual participation on recovery were slightly larger than on prevention, though this was not entirely clear from the data. Overall, however, what was clear was that, in several settings, religious and spiritual participation lowered substance use and abuse.

Because we were trying to move towards knowledge, not just provide additional evidence, we also considered numerous alternative possible explanations for the results, and used sensitivity analysis techniques to assess the possibility of a variety of biases. Restricting to large longitudinal studies with control for baseline outcome certainly helped in itself. Sensitivity analysis for potential unmeasured confounding indicated that this was unlikely to explain away the effect: an unmeasured confounder would essentially have to increase service attendance and decrease substance abuse by more than 50 percent each, above and beyond everything already controlled for, to explain things away. Sometimes “publication bias” can also be a concern, where only certain studies are published in the literature, and others never make it in. The various sensitivity analyses for such publication bias also suggested this could not explain things away, and even an analysis of the least favorable studies, when synthesized, suggested a protective effect.

Evidence from a single study is rarely definitive, but here, when combining such evidence across a large number of the most rigorous studies, it becomes difficult to find any other explanation than that various forms of spirituality and religion have a protective effect on substance use. Nonetheless, we should still be cautious as to what it is that we actually know: most of these studies come from the Western world, so are not necessarily generalizable across cultures. Nor is the claim that religion and spirituality always have such protective effects. Rather, what we can say quite definitively is that in at least some contexts, certain spiritual practices and perhaps especially participation in religious communities decrease substance use and abuse.

Implications

The implications of these results need to be treated with some nuance. This does not constitute grounds for any sort of uniform prescription for religion. However, the results do point towards religion and spirituality as important resources in potentially preventing and recovering from substance abuse. These findings are of potential public health relevance. Large portions of our nation and of our world positively identify with a religious tradition. Clinicians, counselors, social workers, and others should be aware of these important resources and encourage them when appropriate. While a uniform prescription of religious service attendance for all is not warranted, when someone does positively self-identify with a religious tradition, it would, as we’ve argued elsewhere, generally be reasonable to encourage participation in a religious community as an important source of support and healing. For those who are not religious, other forms of community participation can be encouraged. Such encouragement can thus be done in a thoughtful, sensitive, and ethical manner. Religious communities can also often offer services for healing from issues of substance abuse, such as, for example, Alcoholics Anonymous programs, which prior evidence indicates have themselves been very effective.

Many today find themselves trapped in patterns of substance abuse and addiction. The turbulent nature of life today, from bombardment by news and social media, to political challenges and polarization, to tumultuous global events, may render such challenges with substance use more severe. We need to draw upon the full range of the resources we have to provide healing and to support flourishing. Spirituality and religious communities can contribute in profound ways, and we should more often appreciate, make use of, and take their extraordinary potential seriously.