The underrepresentation of racial/ethnic minorities in research on co-use of nicotine, alcohol, and/or cannabis via ecological momentary assessment methods: A narrative review.

Background: Co-use of nicotine, alcohol and/or cannabis is common among adults in the United States. Co-use may represent greater addiction severity than single substance use. Recent studies have examined the extent to which the frequency, order, simultaneity, motivations, and contextual factors associated with co-use differ from that of single use. Co-use has become prevalent among racial/ethnic minority individuals who exhibit distinct co-use patterns and related outcomes; however, most of these studies rely on cross-sectional or sparse longitudinal observations. Ecological momentary assessment (EMA) can illuminate such patterns and associations with time-varying contexts. This review summarizes EMA studies on co-use published from 2008 to 2023 involving racial/ethnic minority individuals and point to gaps. Our review addresses: 1) whether use of one substance leads to substitution or complementary use of another, 2) whether antecedents/contexts differ by co-use patterns and minority status, and 3) what consequences of co-use have been documented across co-use patterns or minority status.

Methods: Search results yielded 465 articles, with 33 meeting inclusion criteria. We extracted study-level characteristics and synthesized the findings.

Results: The findings largely focused on co-use patterns, categories of co-use, proximal antecedents and contexts, and consequences. Variations by minority status were rarely examined; few examined acute effects of unique experiences that may contribute to co-use among racial/ethnic minority adults.

Conclusions: The EMA literature on co-use is burgeoning in recent years and supports complementary hypothesis. More research to capture time-intensive data on experiences to contextualize the co-use among racial/ethnic minority groups with greater diversity in race/ethnicity is warranted.