The results of this study demonstrate a clear polygenic contribution from common autosomal genetic variants to ADHD in both sexes, as evidenced by moderate SNP-h2 estimates using two methods (similar in both sexes once nonrandom sample ascertainment is taken into account via sample size matching), clear deviation of test statistics on sex-specific GWAS quantile–quantile plots, and significantly higher overall PRSs in cases compared with sex-matched controls. Top hits from sex-specific GWAS analyses corroborate results from a combined analysis of both sexes (7).
