Based on literature that suggests socioeconomic status (SES) can impact brain development (Hackman, Farah, & Meaney, 2010), we covaried for family SES as indexed by parental report of highest education in COGA Phase 1–3. Analyses including APOEε4 also covaried for the first ten genetic principal components (PCs) derived from the genome-wide data to account for population structure (Price et al., 2006).
