PRS analyses were done using GWAS summary statistics from 22 GWASs (Supplementary Table 11). The summary files were downloaded from public databases and processed using the munge script which is a part of the LDscore regression software74. All variants with INFO < 0.9, MAF < 0.01, missing values, out of bounds P-values, ambiguous strand alleles and duplicated rs-ids were removed using the munge script. In addition, mult-allelic variants and insertion and deletion (indels) were removed. The processed summary files were then LD-clumped using Plink, with the following parameter settings: --clump-p1 1 --clump-p2 1 --clump-r2 0.1 --clump-kb 500. The clumped file were used as the training dataset. Genetic risk scores were estimated at different P-value thresholds for SNP inclusion: 5x10−8, 1x10−6, 1x10−4, 1x10−3, 0.01, 0.05, 0.1, 0.2, 0.5 and 1.0 for all individuals in the target sample (CUD cases and the control group) from the genotype dosages using Plink’s ‘--score’ method, with default arguments. However the PRS scores for ADHD, were generated using the approach described Demontis et al.33. For each P-value threshold the variance in the phenotype explained by PRS
