CRP and depressive disorder: For example, a meta-analysis of 22 studies showed that ACEs were positively associated with several inflammatory markers, including C-reactive protein (CRP), a protein produced by the liver that is frequently used as an index of chronic low-grade inflammation and correlates with cerebrospinal fluid samples of inflammatory cytokines implicated in depression (Felger et al. 2020; Orsolini et al. 2022; Zagaria et al. 2024).