CRP and major depressive disorder: Differences in C2 levels between MDD cases and controls were of small effect size (Cohen’s d = 0.2) comparable to those previously reported for other biomarkers such as CRP (d = 0.15) [47] and insulin resistance (d = 0.19) [48] Results were confirmed in pooled analyses with >4000 observations additionally including an additional sample with data collected in subjects still available at 6-year follow-up.