Effectiveness of Interventions in Reducing Substance-Related Stigma: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The purpose of this study was to undertake a quantitative analysis to determine the effectiveness of interventions designed in reducing different types of stigma (self-stigma, social stigma, and structural stigma) for the substance use. This study followed the Cochrane Handbook for Systematic Reviews of Interventions guideline. This study followed the Cochrane Handbook for Systematic Reviews of Interventions guideline. Systematic searches were conducted in PubMed, Science Direct, Web of Science, Scopus, and MEDLINE. These electronic databases were searched research published in English from date of their inception to July 15, 2021. Randomized controlled trials that evaluated interventions on stigma associated with substance use were included. Studies should include at least one stigma outcome involving self-stigma, social stigma, or structural stigmatization. Ten randomized controlled studies were included. The overall Hedges'g for the interventions' impact on reducing stigma was 0.301, 95%CI = [-0.154- 0.755], p = 0.195, that there was no statistically significant difference. However, the meta-analysis showed that interventions had no significant impact on self-stigma [0.682, 95% CI=(-0.015-1.380), p = 0.055] and social stigma [0.198, 95% CI=(-1.271-0.876), p = 0.718] but had a small but significant impact in favor of the experimental group on reducing structural stigma [0.360 (95% CI= 0.156-0.564), p = 0.00]. According to subgroup analyses, there was no difference in the effects of stigma according to the type of intervention, the number of sessions, or the type of group. The interventions for reducing stigma related to substance use are promising. It seems to have a small but significant positive impact on structural stigma.