Culturally Adapted Interventions for Substance Use: A Systematic Review and Meta-Analysis

Background and Purpose: Cultural values and beliefs have been shown to have a moderating effect on substance use, thus an increasing number of substance use interventions with Latino adolescents seek to incorporate culture in an attempt to positively impact outcomes. Research on the effectiveness of culturally adapted substance use interventions, however, has produced a body of ambiguous evidence. The purpose of this review is to examine the characteristics and effects of culturally adapted substance use interventions with Latino adolescents on substance use outcomes. The research question guiding this study is: What are the effects of culturally adapted interventions on substance use outcomes with Latino adolescents?

Methods: The present study used systematic review methods and meta-analytic procedures following Campbell Collaboration guidelines and an a priori protocol. A systematic search in thirteen electronic databases, five research registers, five research affiliated websites, reference lists, and a comprehensive gray literature search was undertaken to locate randomized (RCT) or quasi-experimental (QED) studies conducted between 1990 and December 2014 examining substance use outcomes of culturally adapted interventions with Latino adolescents. Two reviewers screened the full text of potentially relevant studies and two reviewers coded all included studies. Descriptive analysis was conducted to examine and describe characteristics of included studies. Effect sizes were calculated using the standard mean difference effect size statistic, corrected for small sample size (Hedges’ g), Meta-analysis, assuming random effects models using inverse variance weights, was used to quantitatively synthesize results across studies.

Results:  The search yielded 35,842 titles and abstracts, and the full texts of 108 articles were screened for inclusion. The final sample included 10 studies (7 RCT and 3 QED). The interventions were conducted in a community organization (n = 6) or school setting (n = 4). The program participants were comprised of 56.5% males, 74.2% were US born, and had a mean age of 13.2 years. All of the interventions were short term (less than 16 weeks) and the majority used CBT or BSFT methods (70%). Meta-analytic results suggest moderate significant effects on substance use outcomes (g = 0.51; CI, 0.012, 1.022). Homogeneity analysis revealed the effect size distribution was heterogeneous, indicating significant variance in magnitude of effects across studies.  Moderator analysis revealed differences in mean effects on study and intervention characteristics. The risk of bias assessment revealed most studies were at high risk for performance bias and selection bias.

Conclusions and Implications: Support for culturally adapted interventions continues to grow, but the specific components and mechanisms that contribute to the efficacy of these interventions for substance use remain unclear. While some culturally adapted substance use interventions demonstrated positive impacts on substance use, there was significant variability across studies. Moreover, the effects on specific substance use outcomes at post-test and follow-up timeframes are not consistently reported. In addition, this review uncovered methodological shortcomings and gaps in the evidence-base that are important for future research in this area. These findings contribute evidence to the ongoing development of policy and practice as legislators and practitioners debate the utility of culturally relevant services.