IFNG and major depressive disorder: Regarding the association of neuroinflammation with depression, there is significant evidence demonstrating that elevated levels of selected cytokines in the periphery (IL-1, IL-6, and IFNγ) and other pro-inflammatory mediators (high sensitivity C-reactive protein or hsCRP) influence the occurrence and progression of MDD episodes (Kim et al., 2016; Al-Hakeim et al., 2018) as well as decreased DA signaling and increased glutamate release with associated excitotoxicity (see Figure 1).