Faith in a higher power appears to have less of an influence on substance use and abuse than previously believed, according to a new study.

Many substance abuse programs, including Alcoholics Anonymous, include religious or spiritual elements. Some past research has indicated that religiousness and spirituality are associated with reductions in substance abuse.

But the new study of 285 monozygotic twin pairs found that religiousness and spirituality had little effect on substance use or abuse once shared genetic effect and shared environmental factors were controlled for. In other words, the findings suggest that genetic and environmental factors shared by religious and spiritual people explain the observed reductions in substance abuse.

The study was published in the Journal of Drug Issues on February 16, 2017.

PsyPost interviewed the study’s corresponding author, Joseph L. Nedelec of the University of Cincinnati. Read his responses below:

PsyPost: Why were you interested in this topic?

Nedelec: As with many ideas for academic studies, this one was the product of discussion shared between my co-author and I over drinks at a pub (ironically enough). During a break from an evolutionary psychology conference we were discussing the influence of genetic factors on behavioral phenotypes. With his interest in substance use and counselling, George was curious about how behavioral genetics tied to his area. The discussion focused on how the link between factors related to counselling — such as religiousness and spirituality — and substance use/abuse may be confounded by genetic factors.

In the end, we decided on a twin-discordance method to ascertain the extent to which religiousness and spirituality (as unique components of the nonshared environment) were related to substance use and abuse once shared genetic and shared non-genetic factors were taken into account. In other words, what was the non-genetically confounded effect of religiousness and spirituality on substance use and abuse?

What should the average person take away from your study?

It appears that once shared genetic factors (in the aggregate) are accounted for, there is little effect of religiousness and/or spirituality on substance use (alcohol or drugs). In other words, as a method of substance use prevention religiousness and/or spirituality do not appear to be influential causal agents. The only association we observed in our genetically-sensitive models was a reduction in general alcohol use in those who scored higher on religiousness (but, there was no association in terms of problematic alcohol use or any type of illicit drug use).

Are there any major caveats? What questions still need to be addressed?

There are two substantial caveats for this study. First, the data analyses were conducted on MZ twins. Thus, to the extent that MZ twins differ from non-MZ twins the results should be tempered accordingly. However, we conducted analyses estimating the differences on the study variables between MZ twins and non-MZ twins in our nationally representative dataset and the differences were minimal. Second, our analyses did not address issues related to treatment. The respondents were community-based (i.e., not clinical) and so our results do not directly relate to the dynamic between religiousness and substance use treatment. This aspect of our study is the most pressing question that still needs to be addressed (i.e., to what extent are genetic factors confounding the association between religiousness/spirituality and substance abuse treatment outcomes?).

Is there anything else you would like to add?

As with many behavioral genetic methodologies, our study highlights the importance of accounting for genetic factors when assessing the associations between variables of interest to social scientists. Key to this point is the fact that our analyses (and most twin-discordance analyses) was not focused on the genetic effect, but the remaining non-genetic (or environmental) effect in a genetically-sensitive model. Such analyses allow us to more accurately pin-point aspects of the environment that are malleable and can help in alleviation of social ills that are of interest to social scientists and practitioners.

The study, “Religiousness, Spirituality, and Substance Use: A Genetically Sensitive Examination and Critique“, was also co-authored by George Richardson and Ian A. Silver.