Leveraging epidemiological data to inform the development of a just-in-time adaptive intervention for young adults co-using e-cigarettes and cannabis

Emerging evidence indicates that co-use of cannabis and e-cigarettes may perpetuate dependence on both products and lead to adverse health outcomes in young people. Thus, there is an urgent need to examine the unique risk factors that drive higher substance use among young adults and rapidly translate findings into scalable interventions. Despite e-cigarette and cannabis co-use being common, it has not been studied in young adults representing unique geographical regions such as Hawaii. The current phased study will utilize epidemiological data from two sources (R61 phase) – the cross-sectional Behavioral Risk Factor Surveillance System (BRFSS) and the longitudinal Young Adult Health Behavior Survey (YAHB) – to guide the development of a Just-in-Time Adaptive Intervention (JITAI) for e-cigarette and cannabis co-use (R33) among young adults ages 18-30 from Hawaii. JITAIs allow for intervention components to be delivered in real-time through a smartphone application. In the R61 phase, we will identify the relative importance of various psychosocial determinants in predicting co-use among young adults. Across both surveys, we will examine associations between e-cigarette and/or cannabis use, rates (prevalence and proportion of use), patterns, and progression (initiation, escalation, and maintenance), with social (e.g., family/peer influence and substance use), community, and advertising/marketing influences. We hypothesize that low-income young adults will be identified as the most susceptible group for co-use and that social influences will be most highly associated with use, initiation, escalation, and maintenance. Findings will allow us to calibrate the proposed intervention and tailor the balance of JITAI components in the R33 phase. Following initial development of the new JITAI, we will conduct a pilot and qualitative interviews with 10 low-income young adults engaging in co-use to assess feasibility. After additional intervention refinements, we will conduct an RCT (2-group) of the JITAI with young adults recruited from community sources who co-use e-cigarettes and cannabis assigned to intervention (n=60) or ecological momentary assessment-only (n=60) to examine its impact on frequency and problem e-cigarette and/or cannabis use.