CXCL8 and major depressive disorder: The results indicate that in males exclusively, Vol_cluster1 (left PHG) significantly mediated the relationship between IL-8 and depression (indirect effect = 0.087, p = 0.035; Figure 6E), as well as Vol_cluster4 (areas in upper part of left precentral and postcentral gyri) (indirect effect = 0.080, p = 0.041; Figure 6H).