DLG2 and major depressive disorder: This study showed that short-term administration of ATRA at a dose of only 10 mg/kg induced depression-like behavior in young mice, accompanied by a decreased expression of DLG2 and an increased expression of SynDIG1. In addition, DLG2 in the hippocampus was correlated with anxiety-like behavior, and SynDIG1 was correlated with depression-like behavior.