Revealing patterns of indigenous neglect in co-occurring posttraumatic stress and substance use disorder research: A...

American Indian/Alaska Native (AI/AN) and Native Hawaiian/Pacific Islander (NH/PI) peoples experience disproportionate burdens of posttraumatic stress disorder (PTSD) and substance use disorder (SUD), which frequently co-occur (PTSD/SUD). Historical trauma, structural inequities, and discrimination may exacerbate the severity and chronicity of these disorders. This review aimed to assess the extent to which PTSD/SUD clinical research includes these Indigenous groups and whether interventions are designed or adapted to meet their specific experiences and risk factors.

We conducted a systematic review of PTSD/SUD studies in the United States. From 135 studies identified in prior systematic reviews and meta-analyses, 66 studies met inclusion criteria. We extracted participant demographic data to quantify Indigenous (AI/AN and NH/PI) representation, assessed whether interventions tested effectiveness across racial groups with attention to Indigenous participants, examined whether interventions were culturally adapted for Indigenous groups, and evaluated whether studies that included higher proportions of Indigenous participants employed distinct recruitment strategies or methodological approaches.

Indigenous participants comprised only 2.2% of all participants. Over half of all studies failed to include Indigenous participants. Only one study tested a culturally adapted intervention. In contrast, over half of studies recruited women or veterans and studied their challenges. Only two studies evaluated outcomes by race, yet neither included Indigenous people. Studies that included higher numbers of Indigenous participants often recruited women exposed to violent trauma or veterans in regions with larger Indigenous populations; however, most studies recruited few or no Indigenous participants regardless of population or location.

We identified a pattern of Indigenous neglect marked by underinclusion, a lack of attention to Indigenous groups relative to other groups, and insufficient evaluation of treatment outcomes for these groups. These issues limit our understanding of what works for Indigenous groups with PTSD/SUD. We make recommendations for addressing these issues.