PRSs were created in GS using raw genotype data using the software PRsice37 using the GWAS summary statistics from the UKB GWAS of alcohol consumption. PRSs were created using P-value thresholds ranging from 0.01 to 0.5 in increments of 0.01 using LD pruning parameters of r2=0.1 over 250 kb windows. The PRS P-value threshold found to explain most of the variance in alcohol consumption in GS was at 0.42 and hence this PRS was used to test for association in subsequent analyses. Association between alcohol PRS and traits of interest was performed in AS-Reml-R and an inverse relationship matrix created from the pedigree information in GS was used to control for relatedness in the sample. Four principal components were fit as fixed-effect covariates to control for population stratification. All traits and PRS were scaled to have a mean of 0 and a s.d. of 1 such that the βs reported are standardized. The variance explained by PRS was calculated by multiplying the PRS by its regression coefficient. This value was divided by the variance of the phenotype analysed to give
