This study was a collaboration between investigators on the PGC MDD and CHARGE genome-wide association meta-analyses (GWAMA). In the discovery phase, we aggregated two GWAMA published in 2013 (7, 14). Basic descriptive features and phenotype definitions of the contributing samples are provided in Table S1. The mega-analysis of MDD consisted of nine studies of 9,240 cases meeting international criteria for lifetime MDD and 9,519 healthy controls. The CHARGE meta-analysis of depressive symptoms included 22 cohorts and comprised 51,258 persons. Each cohort contributing to the GWAMA of the PGC and CHARGE were distinct. In the replication analyses, 16 case-control studies with DSM-IV MDD (6,718 cases and 13,453 controls) were included along with 8,157 subjects from the general population with assessment of depressive symptoms. All subjects were of European ancestry. Institutional review boards approved all studies and all participants provided written informed consent.
