We conducted a GWAS meta-analysis of 57 BD cohorts collected in Europe, North America and Australia (Supplementary Table 1), totaling 41,917 BD cases and 371,549 controls of European descent (effective n = 101,962, see Online Methods). For 52 cohorts, individual-level genotype and phenotype data were shared with the PGC and cases met international consensus criteria (DSM-IV, ICD-9 or ICD-10) for lifetime BD, established using structured diagnostic interviews, clinician-administered checklists or medical record review. BD GWAS summary statistics were received for five external cohorts (iPSYCH30, deCODE genetics31, Estonian Biobank32, Trøndelag Health Study (HUNT)33 and UK Biobank34), in which most cases were ascertained using ICD codes. The GWAS meta-analysis identified 64 independent loci associated with BD at genome-wide significance (P < 5 × 10−8) (Fig. 1, Table 1, and Supplementary Table 2). Using LD Score regression (LDSC)35, the hSNP2 of BD was estimated to be 18.6% (s.e. = 0.008, P = 5.1 × 10−132) on the liability scale, assuming a BD population prevalence of 2%, and 15.6% (s.e. = 0.006, P = 5.0 × 10−132) assuming a population prevalence of 1% (Supplementary
