IL6 and depressive disorder: In depression animal models, studies found that restraint stress stimulated the increased levels of IL-6 (Nukina et al., 2001), and administration of LPS or recombinant IL-6 induced depressive-like behaviors (Dantzer et al., 2008; Hayley et al., 2008; Fu et al., 2010; Sukoff Rizzo et al., 2012).