We observed a significant group difference in CRP (log10) (F(2,92) = 6.041, p < 0.003), with post-hoc comparison revealing a significant increase in patients with SZ compared to HC (p = 0.009, Cohen’s d = 0.793) and an increase in patients with SZ compared to patients with MDD (p = 0.009, d = 0.665) with no significant difference between HC and MDD (p = 0.636, d = 0.147). This evidence concerns the gene CRP and major depressive disorder.