SNP heritability (h2SNP) and pair-wise genetic correlation among the cohorts were calculated using LD score regression79 analysis of summary statistics from GWAS of deCODE samples, meta-analysis of iPSYCH1+iPSYCH2 and meta-analysis of the 10 PGC cohorts (applying the same approach as described for the meta-analysis of all cohorts). Conversion of h2SNP estimates from observed scale to the liability scale was done using a population prevalence of 5%. Test for significant differences in h2SNP between cohorts was done using a Z-test.
