The efficacy of spiritual/religious interventions for substance use problems: A systematic review and meta-analysis of randomized controlled trials

Background: Spiritual/religious (S/R) interventions are commonly used to treat substance use problems, but this is the first systematic review and meta-analysis to examine their efficacy for these problems. Methods: Ten electronic databases were searched to identify eligible studies (i.e., randomized controlled trials) published between January 1990 and February 2018 that examined S/R interventions' efficacy for substance use or psycho-social-spiritual outcomes. Two reviewers independently screened studies, extracted data, and assessed risks of bias. Robust variance estimation in meta-regression was used to estimate effect sizes and conduct moderator analysis. Results: Twenty studies comprising 3700 participants met inclusion criteria. Four studies used inactive controls, 14 used active controls, and two used both inactive and active controls and were therefore included in estimating both absolute and relative effect sizes. The absolute effect of S/R interventions (compared with inactive controls such as no treatment) was moderate but non-significant (six studies, d = .537, 95% confidence interval [CI] = -.316, 1.390), possibly due to low power. The relative effect of S/R interventions (compared with other interventions) was statistically significant (16 studies, d =.176, 95% CI =.001, .358). Because only 12-step oriented interventions were compared with other interventions, this finding does not apply to the relative effect of non-12-step-oriented S/R interventions. Moderator analysis showed that relative effect sizes differ significantly by country. Conclusion: We found evidence of S/R interventions' efficacy in helping people with substance use problems. More high-quality efficacy studies of non-12-step-oriented S/R interventions for substance use problems are needed.