Kruse et al. [32] found that an increase in IL-8 from baseline to 24 hours postinfusion was associated with a favorable depression treatment response in females and an unfavorable treatment response in males (females: p = 0.095, effect size (sr2) = 0.16; males: p = 0.96, effect size (sr2) < 0.01). Here, CXCL8 is linked to major depressive disorder.