Among our findings, the important result was that MnSOD activity and cognitive performance were significantly correlated in SZ patients with Val homozygotes, suggesting that oxidative stress may be implicated in the psychopathological mechanisms of cognitive impairment of schizophrenia patients, and the use of antioxidants is a possible option for the treatment of cognitive decline in patients with first-episode SZ in the clinical practice. The gene discussed is SOD2; the disease is Mental deterioration.