Simultaneous alcohol and cannabis use in young adults: A micro-randomized trial to reduce substance use and related harms

About This Grant

PROJECT SUMMARY/ABSTRACT Young adults’ simultaneous use of alcohol and marijuana/cannabis (SAM) is prevalent, increasing, and associated with heavy substance use and risk for substance-related harms. Scant research has focused on intervention programming for SAM use, and effects on use behaviors have been small to non-existent. Mobile app-based interventions are a promising option for delivering real-time intervention in moments of highest risk for young adult substance use. Given their ability to tailor based on features of a day (e.g., situations, motivations, mental health symptoms), app-based interventions are ideal for mitigating SAM-related harms. Mindfulness-based interventions (MBIs) and protective behavioral strategy (PBS) interventions are useful in distinct contexts, making them ideally suited for addressing individual determinants of SAM use in daily life. A micro-randomized trial (MRT) that randomizes the delivery of intervention content each day is the ideal, gold- standard approach for identifying whether and when distinct real-time intervention content is most effective. Toward our team’s ultimate goal of developing a novel app-based just-in-time intervention (JIT), we aim to conduct the first MRT with daily-level randomization to MBI, PBS, or no intervention among young adults who engage in SAM use. This R01 application has three aims: 1) To refine and co-curate with young adults digital MBI and PBS content to deploy in real time; 2) To conduct an MRT with daily level randomization (MBI, PBS, no intervention); and 3) To test time-varying moderators of intervention efficacy. We propose two studies within this R01, both with college- and non-college-attending young adults (ages 18-25) who report SAM use and frequent heavy episodic drinking and reside in Oregon or Washington. In Study 1 (n=1000), our team will gather quantitative and qualitative data on acceptability of MBI and PBS content (text, audio, visual) and ideas for improvement. In Study 2 (n=300), we will refine our intervention and then conduct an MRT in preparation for optimizing a future JIT. After completing a digital foundational module, participants will complete a brief daily diary for 45 days on behaviors that occurred the prior day, their current state, and planned behavior. Each day, participants will be randomized to 1 of 3 intervention conditions: MBI, PBS, or no intervention content. On each MBI and PBS intervention day, participants will receive unique intervention content 3 times (late morning, afternoon, early evening) to their mobile device. Our team will measure efficacy of the intervention on 3 same- day outcomes—substance-related harms, SAM use, and level of alcohol use—in addition to identifying features of days (e.g., an individual’s substance use motives) when distinct intervention content was more or less effective. Findings from this work will directly inform and prepare us to launch a JIT to deliver intervention content that changes in response to features of the day, meeting individuals in moments of greatest risk.