Ancestry-specific discovery GWAS were used to generate PGS for the following phenotypes (Table 3): alcohol phenotypes (i.e. Drinks/Week (Saunders et al., 2022), Problematic Alcohol Use (Kranzler et al., 2019; Zhou et al., 2020)), internalizing (i.e. major depressive disorder (Howard et al., 2019; Levey et al., 2021), generalized anxiety disorder (Levey et al., 2020), neuroticism (Nagel et al., 2018)), externalizing (i.e. risk tolerance (Karlsson Linnér et al., 2019), ADHD (Demontis et al., 2019), common executive function (Hatoum et al., 2023)). Because the present study examines stage-based behavioral phenotypes in relation to alcohol milestones, we do not use the recent, large externalizing GWAS (Karlsson Linnér et al., 2021) that includes alcohol and substance-related indicators. GWAS were selected based on sample size, relevance to phenotypes implicated in the neurobiological stage-based model, and similarity to the COGA-P phenotypes where possible (Supplemental Methods).
