First, early adult and adult variables were simulated from a multivariate normal distribution with mean equal to 0 and correlation equal to the observed point estimate of the genetic correlation between early adult and adult alcohol use frequency using the mvtnorm package (Genz et al. 2021; Genz & Bretz, 2009) in R (R Core Team, 2017). A SNP variable was simulated as two draws from a binomial distribution to model a diploid genotype with probability equal to varying values for MAF (.01, .10, .20, .30, .40, .50). The adolescence variable was simulated from a normal distribution with the mean and variance conditioned on the early adult variable, the adult variable, and the SNP. The effects of the early adult variable and the adult variable on the adolescence variable were set to the corresponding observed genetic correlation point estimates. The effect of the SNP on the adolescence distribution was set to β=0.01. This effect size is comparable to those observed for significant SNPs in a recent GWAS of alcohol consumption (Liu et al. 2019). The variance of the adolescence variable was
