Hispanic participants in the National Institute on Drug Abuse’s Clinical Trials Network: A scoping review of two decades of research

INTRODUCTION: Hispanics significantly underutilize substance abuse treatment and are at greater risk for poor treatment outcomes and dropout. Two decades of research from the National Drug Abuse Treatment Clinical Trials Network (CTN) offers an opportunity to increase our understanding in how to address the disparities experienced by Hispanics in substance abuse treatment. METHODS: A scoping review was utilized to determine what has been learned from the CTN about Hispanic populations with substance use disorder. A systematic search was conducted within the CTN Dissemination Library and nine databases. Potentially relevant studies were independently assessed by two reviewers for inclusion. RESULTS: Twenty-four studies were included in the review. Results identified issues in measurement, characteristics of Hispanic substance use, effective interventions, and gaps for future research. Characteristics that interfere with treatment participation were also identified including low employment rates, less likelihood of having insurance, lower rates of internet access, and increased travel time to services, as were treatment issues such as high rates of alcohol and tobacco use. Effective interventions were identified; however, the effectiveness of these interventions may be limited to specific factors. CONCLUSIONS: Despite efforts to improve inclusion of minority populations, Hispanics remain underrepresented in clinical trials. Future research including Hispanic populations should examine measurement equivalence and consider how cultural and historical experiences, as well as patient characteristics, influence utilization of services. Finally, more studies are needed that examine the impact of structural factors that act as barriers to treatment access and engagement and result in significant disparities in treatment outcomes.