Genetic influences on alcohol use vary throughout development (Aliev et al. 2015; Dick et al. 2006; Edwards & Kendler, 2013; Kendler et al. 2011; Meyers et al. 2014; Sakai et al. 2010). The omission of developmental considerations from gene-identification studies for alcohol use behaviors limits the utility of polygenic scores for phenotype prediction across the lifespan (Elam et al. 2021; Kandaswamy et al. 2021). Recent advances in multivariate genomic methods provide an opportunity to identify genetic variants that account for developmental changes in genetic liability for alcohol use behaviors. In this work, we present an analytic approach for developmentally-informative gene-identification using Genomic SEM. The age-specific PGS predicted an increase of 4 drinking days per year per PGS standard deviation when modeled separately from the common factor PGS in adulthood. Though the discovery analysis in the current work was underpowered, developmentally-informed gene discovery analyses may improve phenotype prediction via polygenic scores when discovery samples are adequately large to model differences in genetic liabilities across development. Beyond applications to polygenic scoring, larger developmentally-informative discovery analyses may also facilitate the identification of age-matched
