PROJECT SUMMARY/ABSTRACT Heavy and frequent alcohol use remains a key public health concern, particularly among young adults. Recent experimental evidence has shown that a single heavy drinking event is associated with short-term structural changes in the brain among a sample of young adults and preliminary diary evidence suggests alcohol use may impact concentration and working memory capacity. As young adults are at highest risk of alcohol use relative to any other age group, such immediate structural changes may signal a need for early prevention and intervention efforts, although the long-term impacts of alcohol use on the brain within a sample of young adults remain unknown. A key indicator of longer-term cognitive outcomes is observed functional impacts on young adult behavior in their daily lives. Changes in daily behaviors during this period could negatively impact cognitive health into midlife. Our team aims to collect intensive data across a 21-day period from a sample of 250 young adults to explore the acute, next-day (post-intoxication) effects of alcohol use on cognitive functioning overall, across multiple timeframes, and by type of drinking episode (light drinking, binge drinking, high-intensity drinking, blackout drinking). We also seek to examine day-level and person-level moderators to inform moments and subgroups at greatest risk and in need of early targeted prevention and intervention efforts. Specifically, the current exploratory and developmental R21 has three aims. Aim 1 will (a) examine acute, next-day effects of any alcohol use on cognitive functioning (episodic memory, executive functioning, working memory) and across various time frames (i.e., upon waking only or persisting throughout the day); and (b) examine whether these daily associations differ by type of drinking episode (light drinking, binge drinking, high-intensity drinking, blackout drinking). Aim 2 will examine day-level moderators (hangover symptoms, mood, sleep, prior day cannabis, other substance use) that may buffer or exacerbate day-level associations between alcohol use (any drinking, light drinking, binge drinking, high-intensity drinking, blackout drinking) and cognitive functioning. Finally, Aim 3 will examine person-level variables (sex, baseline alcohol use severity, general cognitive functioning) as moderators of day-level associations between alcohol use (any drinking, light drinking, binge drinking, high-intensity drinking, blackout drinking) and cognitive functioning. By identifying the acute impacts of varying levels of alcohol use intensity on next-day cognitive functioning as well as the day- and person-level characteristics that moderate these associations, our findings will have critical implications for the role of alcohol use on everyday cognitive functioning and highlight subgroups most in need of monitoring and early intervention. Findings from this exploratory and developmental R21 will also position our team well to ultimately examine whether day-level associations accumulate and are indicative of later alcohol-related and cognition-related problems.

PROJECT NARRATIVE Heavy and frequent alcohol use remains a key public health concern, particularly among young adults. The proposed work will collect intensive momentary assessment data to examine associations between higher-risk alcohol use episodes (binge, high-intensity, blackout drinking) and multiple indices of next-day (post- intoxication) cognitive functioning. By identifying the acute impacts of varying levels of alcohol use intensity on next-day cognitive functioning as well as the day- and person-level characteristics that moderate these associations, our findings will have critical implications for the role of alcohol use on everyday cognitive functioning and highlight subgroups most in need of monitoring and early intervention.