We conducted GWAS meta-analyses of bipolar I disorder (BD I) (25,060 cases, 449,978 controls) and bipolar II disorder (BD II) (6,781 cases, 364,075 controls). The BD I analysis identified 44 genome-wide significant loci, 31 of which overlapped with genome-wide significant loci from the main BD GWAS (Table 1 and Supplementary Table 21). The remaining 13 genome-wide significant loci for BD I all had P < 4.0 × 10−5 in the main BD GWAS. One genome-wide significant locus was identified in the GWAS meta-analysis of BD II and had a P < 1.1 × 10−4 in the main GWAS of BD (Supplementary Table 21). The hSNP2 estimates on the liability scale for BD I and BD II were 20.9% (s.e. = 0.009, P = 1.0 × 10−111) and 11.6% (s.e. = 0.01, P = 3.9 × 10−15), respectively, assuming a 1% population prevalence of each subtype. These heritability values are significantly different from each other (P = 2.4 × 10−25, block jackknife). The genetic correlation between BD I and BD II was 0.85 (s.e. = 0.05, P = 2.88 × 10−54),
