CAT and major depressive disorder: Hence, therapeutic approaches strengthening the antioxidant enzyme potential, including catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD), reducing the malondialdehyde (MDA) level (main end-product of lipid peroxidation), scavenging the other free oxygen species or regularizing the AChE function in different brain areas may have a precautionary effect against NS-induced anxiety, depression and cognitive failure [8,127].