Covid-19 pandemic and changes in the prevalence, patterns, and trajectories of substance use and related health risk outcomes among young adults in WA State: Administrative supplement.

ABSTRACT This is an administrative supplement to the parent study that examines changes in cannabis, alcohol, and tobacco use and related health risk behaviors (e.g., driving while-or riding with a driver-under the influence of cannabis, alcohol, and simultaneous effects of cannabis and alcohol) during the course of COVID-19 pandemic among young adults in Washington State. The parent study uses data from the Washington Young Adult Health Survey (YAHS) that we collected with funding from the Washington State's Division of Behavioral Health and Recovery. YAHS is an accelerated longitudinal cohort sequential study of young adults ages 18- 25, with cohorts added annually and followed over time. The parent study uses data collected between 2015 and 2021, including two cohorts that were added after the onset of the pandemic, and five cohorts that had longitudinal data spanning the time from before to during the pandemic. The work under this supplement will involve the newest data available, collected from this sample in the summer and fall of 2022 (n=7,500). The 2022 data collection period came after mask mandates were lifted and many saw the pandemic as over. This will allow us to examine the longer-term changes in substance use, related health risk behaviors, and substance-specific risk and protective factors. The added wave of data will also be beneficial methodologically by increasing the sample size and the associated statistical power to detect even smaller but clinically meaningful effects. Moreover, in 2022, additional items assessing mental health were included, which will allow us to assess the psychometric properties of the original assessment as well as the continuity of mental health issues, both as consequences and predictors of substance use and related health risk behaviors. We will assess the extent to which patterns (e.g., mode of use, sources, frequency, and amount) of cannabis, alcohol, and tobacco use, simultaneous cannabis and alcohol use, and SU-related risk behaviors (e.g., driving while intoxicated) differ in 2022 compared to earlier years (2015-2021). The role of community-level factors and differences by socio-demographic characteristics (e.g., sex, sexual and gender minoritized status, race/ethnicity, college student status) in these changes will be examined. Because the parent study aims to assess within-person changes in substance use and related risk behaviors (e.g., driving while intoxicated), focusing specifically on initiation, escalation, and desistance, having an additional wave of data will allow us to understand what changes in outcomes were sustained and what changes were limited to the early years of the pandemic, thereby bolstering the original aims of the parent study and improving the precision of planning of prevention and intervention efforts aimed at improving health and reducing problem behaviors over the course of young adulthood.