PROJECT SUMMARY The proposed research study applies positive emotion regulation models to identify within-person and between-person transdiagnostic mechanisms that contribute to comorbid Alcohol Use Disorder (AUD) and Social Anxiety Disorder (SAD). SAD is an important risk factor for the development of AUD, and comorbid SAD and AUD confer greater detrimental effects on public health-related outcomes than either disorder alone. Building on critical foundational work using negative emotion regulation models to explain comorbid AUD and SAD, the current proposal focuses on positive emotion regulation, particularly difficulty accepting positive emotions, which may also play a critical role in driving comorbidity. Past research has established that people high in SAD symptoms have difficulties regulating positive emotions, including difficulty accepting positive emotions. Although people with AUD often experience deficits in positive emotion regulation in their daily lives (i.e., when sober), there is evidence suggesting that, in the short term, alcohol use facilitates adaptive positive emotion regulation. For example, a recent ecological momentary assessment (EMA) study found that alcohol weakened the relation between state SAD symptoms and reported social interaction quality. Specifically, when participants did not consume alcohol, state SAD symptoms predicted worse social interaction quality, but when they did consume alcohol, state SAD symptoms did not affect social interaction quality. Thus, an understudied area of research is whether alcohol consumption temporarily allows individuals with elevated SAD symptoms to accept positive emotions, which, in the long term, could lead to alcohol-related problems. Aim 1: Using EMA methodology, test whether, on a within-person level, alcohol consumption moderates the day-to-day temporal relation between state SAD symptoms and difficulty accepting positive emotions in young adults at risk for both AUD and SAD. It is expected that greater state social anxiety symptoms will predict greater difficulty accepting positive emotions, but alcohol will moderate (weaken) this relation. Aim 2: Test whether, on a between-person level, the extent to which alcohol helps people accept positive emotions is associated with alcohol-related problems across participants. It is expected that the effectiveness of alcohol in reducing the deleterious impact of SAD on difficulty accepting positive emotions will be correlated with greater alcohol-related problems. By clarifying whether alcohol consumption’s benefit to positive emotion regulation (e.g., increasing acceptance of positive emotions) contributes to problematic alcohol use, results of this study may provide preliminary evidence of important public health-related targets for prevention and intervention in those at risk for AUD. This research proposal and corresponding training plan allow the applicant to obtain extensive training in EMA methods and data analysis tools and pr...