IL1B and major depressive disorder: Similarly, elevated expressions of IL-2, IL-10, IL-1β, TNF-α, and/or IFN-γ may be detected in depression, schizophrenia, bipolar disorder, PTSD, and suicidal ideation (Black and Miller, 2015; Irwin et al., 2016; Wang and Miller, 2018; Enache et al., 2019; Yang and Jiang, 2020).