Abstract. Non-alcoholic beverages that seek to mimic alcohol (e.g., non-alcoholic beers, non-alcoholic wines, non-alcoholic liquor, and “mocktails”) are rapidly expanding in popularity and availability, with a 15-30% annual increase in U.S. sales since 2018. Non-alcoholic beverages are most commonly consumed by people who also consume alcohol and consumers often report using these drinks to try to reduce their alcohol use. Research on the relation between non-alcoholic beverage use and alcohol use is needed to inform consumers, clinical providers, and public health professionals about whether non-alcoholic beverages help people to reduce alcohol use (by serving as a substitute) or paradoxically stimulate it (through cue-induced craving). Through the proposed K99/R00 Award, Dr. Bowdring will examine the potential utility vs. harm of non-alcoholic beverages. Ecological momentary assessments (EMA; measures captured in real-time with prompts sent via smartphone) will be used to sensitively test associations between non-alcoholic beverage use and alcohol use among people with alcohol use disorders (AUD) and social drinkers. Aim 1 (K99): Estimate the relation between non-alcoholic beverage use and alcohol use among people with AUD. Participants will be n=102 U.S. adults (ages 21-89) who meet criteria for AUD and regularly consume non-alcoholic beverages. They will complete survey assessments of non-alcoholic beverage use and alcohol cravings, as well as alcohol use measured via portable breathalyzers, multiple times per day across multiple weeks. This study will inform methodological decisions for the R00 study. Aim 2 (R00): Estimate differences in the relation between non-alcoholic beverage use and alcohol use between people with AUD and social drinkers. With a larger sample size to support power in testing differences between two distinct subgroups, the R00 EMA study (n=220) will replicate and build on the K99 study by also recruiting social drinkers in addition to people with AUD. Exploratory Aim 3 (K99+R00): Model the relation between alcohol craving, non-alcoholic beverage use, and alcohol use. In both the K99 and R00 study, the role of alcohol craving in the relation between non-alcoholic beverage use and alcohol use will be explored, offering novel insight into a potential theoretically-informed mechanism. Dr. Bowdring has prior training in lab-based alcohol research with social drinkers and clinical experience as a licensed psychologist working with individuals with AUD. This K99/R00 Award will enable Dr. Bowdring to gain training in: a) best practices for involving people with AUD in research; (b) EMA methods for alcohol research; (c) strategies for leveraging research findings to inform clinical practice and public health policy; and (d) transitioning to research independence. Mentorship will be provided by experts in the fields of clinical research (Prochaska), EMA in alcohol studies (McCarthy, Fairbairn, Trull, Boothroyd), and addiction pre...