Here, we report the third GWAS from the Major Depressive Disorder (MDD) Working Group of the Psychiatric Genomics Consortium (PGC MDD2023), We conducted a genome-wide association mega-analysis of major depression (MD) in 49 cohorts of European ancestry (“MDD49”) with combined 28,147 cases and 48,033 controls (defined by the original study authors, but defined as individuals without MD, schizophrenia or bipolar disorder). We then meta-analyzed the MDD49 results with summary statistics from 24 additional cohorts of European ancestry. We subsequently carried out a multi-ancestry meta-analysis, adding data from 160,611 cases and 1,001,890 controls with diverse ancestry, for a total sample size of 688,808 cases and 4,364,225 controls (the “discovery GWAS”). This sample size has the power equivalent to a balanced study (with equal numbers of cases and controls) with a total sample size of Neff = 2* 1,000,101. For some cohorts, case status was based on self-report and did not reach the formal criteria of MDD. Hence, we use the term major depression (MD) to define case-ness.54
