CRH and major depressive disorder: Total iridoids of V. jatamansi effectively improved the sucrose preference, immobility time, and depression-like behaviors of the depressive mouse model induced by chronic unpredictable mild stress, as well as the levels of 5-HT, norepinephrine (NE), substance P, and corticotropin-releasing factor (CRF) expression in the hippocampus and colon.