BDNF and major depressive disorder: Notably, the presence of many studies on depression is not surprising since the use of magnesium is mostly reserved to depressive disorders, because of its involvement in several core mechanisms of depressive physiopathology, including glutamatergic transmission in the limbic system and cerebral cortex [89], regulation of the HPA axis [41,90], inflammation and oxidative stress [91], response to NMDA receptor antagonist [92], serotonin, dopamine, and noradrenaline modulation [43], BDNF expression [40], as well as the modulation of the sleep–wake cycle [93].