Major depressive disorder (MDD) is a common complex trait of enormous public health significance. As part of the GAIN initiative of the US Foundation for the NIH (19), we conducted a genomewide association study of 435,291 SNPs genotyped in 1,738 MDD cases and 1,802 controls selected to be at low liability for MDD. Our study had numerous positive attributes including its historically large sample size, its largely population-based and longitudinal design, and relatively unbiased and dense genomewide genotyping designed to capture common variation in subjects of European ancestry.
