CX3CR1 and major depressive disorder: Although some authors did not detect depressive-like behavior in CX3CR1-deficient mice [153, 154], and a few even reported that these mice are resistant to the chronic stress-induced depression [155–157], other authors report that CX3CR1-deficient mice show anxiolytic-like and depressive-like phenotypes in females [67] and greater depressive-like behavior in response to LPS-induced inflammation [158].