The significantly higher peripheral IGF-1 levels in the patients than the healthy controls still persisted after subgroups analysis by BD and MDD (ESs = 0.53, 95% CI: 0.22–0.84, P = 0.001; ESs = 0.64, 95% CI: 0.41–0.87, P < 0.001, respectively) (Figure 2A). This evidence concerns the gene IGF1 and major depressive disorder.