IL1B and depressive disorder: Genetic deletion or pharmacological inhibition of Caspase-1 that cleaves IL-1β and IL-18 into their mature isoforms exhibited reduced depression- and anxiety-like behaviors in a chronic restraint stress model, combined with an increase in Akkermansia species that is associated with decreased inflammation and a rebalancing of the gut microbiota (Alcocer-Gomez et al., 2014; Anhe et al., 2015; Yang et al., 2015).