IL1B and major depressive disorder: In addition, in some animal models of depression, brain IL-1β expression was increased and treatments with IL-1ra, deletion of IL-1R1, or inhibition of inflammasome activities, required for the production of active IL-1β, have been shown to reduce depressive-like behaviors (Barrientos et al., 2003; Li et al., 2021, 2023; Koo et al., 2009; Xia et al., 2023).