CAT and schizophrenia: In patients with schizophrenia, correlation analyses showed that H2O2 concentration was significant positively associated with the PANSS positive symptoms score (r = 0.307, P = 0.006), CAT activities and MDA levels were significant negatively correlated with the PANSS negative symptoms score (r = -0.366, P = 0.001; r = -0.241, P = 0.032; respectively) and the PANSS total score (r = -0.302, P = 0.006; r = -0.271, P = 0.015; respectively).