In fact, several meta-analyses confirm the association between depression and increased inflammation, with depressed patients showing elevated levels of IL-6, IL-1, TNF-α and C-reactive protein (CRP) compared with healthy controls (Dowlati et al., 2010, Horn et al., 2018, Howren et al., 2009, Perrin et al., 2019). This evidence concerns the gene CRP and depressive disorder.