Developing and Testing an Online Intervention for Decreasing Alcohol and Cannabis Misuse and Increasing Healthy Relationship Skills among Young Adult Couples: A Comprehensive Mixed-Methods Approach - Project Abstract Co-use of alcohol and cannabis (using both substances, either simultaneously or concurrently) represents a significant public health concern among young adults (YAs), as co-use of these substances is common and worsens alcohol-related harms. However, YAs are unlikely to seek treatment for their substance use, and existing brief interventions (BIs) for alcohol and cannabis misuse produce modest effects. Thus, there is a critical need to explore novel treatment components to increase participant engagement and maximize effects. From a social-developmental perspective, romantic partners have the strongest social influence on YA substance use, and an underexplored area for intervention. Dyadic research suggests romantic couples mutually influence each other’s substance use, increasing risk for greater substance use involvement and more negative interpersonal consequences. Whether these associations extend to or are exacerbated by co- use remains understudied. Crucially, there is no known BI for co-use among YA couples. This innovative study seeks to fill these gaps in two phases. Phase 1a: 75 YA couples will provide 30 days of daily reports on alcohol and cannabis use, co-use, negative (e.g., conflict) and positive interpersonal consequences (e.g., intimacy), and relationship outcomes (e.g., satisfaction). Multilevel models will test whether a person’s co-use is associated with a greater likelihood of their partner co-using. Multilevel Actor Partner Independence Models will test if couples experience greater negative consequences, fewer positive consequences, and poorer relationship functioning on days when both partners report co-use than on days when only one partner reports co-use, and vice versa (consequences → next day co-use). Phase 1b: 15 participants from Phase 1 will participate in qualitative interviews to assess treatment need and inform intervention content. Data and rapid prototyping (Phase 1 c) will inform development of an online, couples- based BI aimed at decreasing co-use and promoting healthy relationship skills. Phase 2: A second cohort of co-using YA couples will be randomly assigned to the intervention (n = 15 couples) or control (n = 15 couples) and complete baseline, post-assessment, and 3-month follow-up surveys testing feasibility, acceptability, and initial support. Completing this research will support my development as an independent alcohol and cannabis researcher with a focus on developing novel interventions for high-risk YA populations. To achieve my career objectives, I require additional training in 1) social-interpersonal influences that impact etiology, maintenance, and treatment of alcohol and cannabis use among YAs in romantic relationships, 2) couples-based intervention delivery, 3) dyadic ecological momentary assessment research and dyadic data analysis, 4) user-centered design, and 5) randomized control trial (RCT) design. The project will provide pilot data for an R01 submission to NIAAA which will test efficacy of the intervention in a full-size RCT.
