To explore the genetic relationship of cross-disorder genetic risk with other traits, we treated this 8-disorder GWAS meta-analysis as a single “cross-disorder phenotype.” We applied LDSC to estimate SNP heritability (h2SNP) and genetic correlations with other phenotypes, using block jackknife-based standard errors to estimate statistical significance. The estimated h2SNP of the cross-disorder phenotype was 0.146 (SE 0.0058; observed scale). Using data for 25 brain-related traits selected from LDHub (Zheng et al., 2017), we found significant genetic correlations of the cross-disorder phenotype with seven traits (at a FDR-corrected p-value threshold 0.002): never/ever smoking status, years of education, neuroticism, subjective well-being, and three sleep-related phenotypes (chronotype, insomnia, and excessive daytime sleepiness) (Table S7.1).
