An estimated RR of 0.58 (95% CI: 0.43–0.79) was obtained after the data were pooled, and a significant effect on the rate of depression was found for the prophylaxis of SSRIs to prevent PEG-IFN-α/RBV-associated depression in patients with CHC (P = 0.0005) (Figure 2). This evidence concerns the gene IFNA1 and major depressive disorder.