PROJECT SUMMARY / ABSTRACT The COVID-19 pandemic, best characterized as a disaster, is unprecedented in its impact on individuals, societies, and the economy. Of special consideration is the effect of the pandemic on the psychological wellbeing and behavior of young people. Here, we propose leveraging the longitudinal, multi-site National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA) study (2012-2022) to investigate changes in wellbeing and behaviors, with a focus on alcohol use in response to the pandemic, in an established sample of young people including moderate-heavy users and those at risk for alcohol use, and to identify risk and protective factors for distress in response to the pandemic. Using NCANDA, we are able to directly address research objectives of NOSI NOT-OD-20-097 to understand social, behavioral and economic impacts from containment and mitigation efforts implemented to reduce spread of the COVID-19 disease, as well as downstream health impacts including substance use/abuse, and to determine risk and resiliency factors and outcomes. Unlike most research in this area, NCANDA includes neurobiological data critical to complement clinical and self-report data in understanding the complex and dynamic interactions leading up to and following a disaster. Also, with its accelerated longitudinal design and current age of participants spanning 17-28 years old, NCANDA is uniquely powered to disentangle age and pandemic related effects, unlike traditional same-age cohort designs. We propose supplementing the NCANDA project with a brief COVID-19 survey about alcohol use, mood, and other behaviors during the pandemic as well as COVID-19 exposure and pandemic-related distress, administered to participants in June 2020. To track long-term effects of the COVID-19 pandemic, the survey will be re-administered in Winter 2020 and Summer 2021. By embedding this survey, time-linked to the pandemic, within the existing NCANDA dataset, we propose characterizing the impact of the COVID-19 pandemic on alcohol use, mental health, and brain in young people (Aim 1) and to evaluate risk and resilience factors for COVID-19 pandemic-related distress (Aim 2). We propose using advanced analytics, including machine learning approaches, to identify a `signature' from the rich information captured by neuroimaging, clinical and self-report data prior to the COVID-19 pandemic, that predicts distress versus resilience in the face of the COVID-19 pandemic. A machine-learning approach embraces the complexity of the COVID-19 pandemic-related influence and takes advantage of the multi-domains within the NCANDA dataset. The analysis proposed in this supplement will offer valuable longitudinal data in a well-characterized sample of young people who are bridging developmental years into adulthood and that includes those at high risk for, or current heavy users of, alcohol. Such information can be used to guide public health and intervention strategies to benefit vulnerable young populations in the event of future disasters.