SOAT1 and major depressive disorder: Elevated IFN-γ concentrations have been found in various neurodegenerative diseases and psychiatric disorders, and we have shown that IFN-γ can activate microglia by stimulating the JAK/STAT pathway to impair adult hippocampal neurogenesis and cause depression-like behaviors and cognitive defects (Mount et al., 2007; Moritz et al., 2017; Zhang et al., 2020a).