Top loci from the ADHD GWAS showed moderate concordance across the three replication studies. Sign concordance between each of the three replication cohorts and the ADHD GWAS was significantly greater than would be expected by chance (range 72–82% concordant; P < 0.0167 = 0.05/3 replication cohorts; Supplementary Table 12) for nominally associated loci from the ADHD GWAS (P < 1 × 10−6), with the highest concordance observed in EAGLE/QIMR. The deCODE and 23andMe results also permit direct comparisons of the magnitude of effect sizes for the top loci in the ADHD loci (Supplementary Table 13). Regressing effect size estimates from each replication cohort on estimates from the ADHD GWAS adjusted for winner’s curse yields significantly positive slopes (deCODE slope = 0.664, P = 1.2 × 10−4; 23andMe slope = 0.417, P = 1.11 × 10−3), although these slopes are less than one, suggesting imperfect replication. Among the genome-wide significant loci, rs9677504 (SPAG16 locus) in deCODE and rs112984125 (ST3GAL3/PTPRF locus) and rs212178 (LINC01572 locus) in 23andMe are noteable outlers with weak replication results (Online Methods, Supplementary Figure 16–17).
