To assess the impact of age-at-death on expression differences between SCZ cases and controls, we compared the per-gene differential expression t-statistics derived from various subsets of the entire cohort described here. Specifically, for the 172 cases and controls whose age of death was youngest (mean age 45.5, range 20–60), the t-statistics for differential expression were highly correlated with those from the full cohort (Pearson r = 0.62), yet somewhat lower (though not significantly, P = 0.28) than for 100 random subsets of the same size (mean r = 0.69, standard deviation = 0.13), suggesting that age at death may have only a modest impact among adult cohorts. Furthermore, we explicitly compared the differential expression between the aged 20–60 individuals (172 samples, mean age 45.5) to an analysis of the complementary age 60 or older cohort (362 cases and controls, mean age 77.8) by independently processing the data for each of those sub-cohorts. The differential t-statistics between these independent sub-cohorts were correlated (r = 0.18, P < 2 × 10−16), arguing for some consistency of case-control differences across the lifespan. Still,
