FOXO1 and major depressive disorder: Interesting studies involving patients with major depressive disorder revealed an increase in SGK1 and FOXO1 expression following polarization of monocyte-derived macrophages towards the M2 phenotype with IL-4 or dexamethasone, and similar results were observed for ketamine-stimulated macrophages, whereas combined treatment with LPS and IFNγ elevated SGK1 but not FOXO1 levels [98].