BDNF and major depressive disorder: In fact, a report showed that mice with depression-like behavior induced by chronic unpredictable mild stress (CUMS), after 7 weeks of treatment with HTyr, performed significantly better in forced swimming and tail suspension tests, in association with reduced oxidative stress—through enhanced SOD activity—and with increased number of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes, as well as increased activity of the BDNF/TrkB/CREB signaling pathway [226].