Oxidative mechanisms in schizophrenia and their relationship with illness subtype and symptom profile

AIM: The aim of the present study was to investigate the differences in the antioxidant-oxidant balance (AO-OB) between schizophrenic patients and healthy individuals and to explore the relationship of AO-OB with illness subtypes and symptom profiles. METHODS: After a 15-day drug-free period, schizophrenia patients (n = 50) in a clinical sample, and age- and sex-matched healthy subjects (n = 49) were enrolled. Total antioxidant potentials (TAOP) and total peroxide levels (TPEROX) of all participants were measured and the oxidative stress index (OSI) was calculated. The assessment included structured measurements, including the Positive and Negative Syndrome Scale (PANSS), and the Brief Psychiatric Rating Scale (BPRS). RESULTS: TAOP had a significant positive correlation with age at onset of schizophrenia (P = 0.013), a negative correlation with the PANSS negative subscale scores (P = 0.008), a negative correlation with the PANSS total scores (P < 0.001), and a significant negative correlation with BPRS scores (P = 0.001). OSI had a significant negative correlation with age at onset (P = 0.046) and a significant positive correlation with PANSS negative subscale (P = 0.015). A multiple regression model indicated a significant linear combination of age, gender, duration of illness, subtype of schizophrenia, and PANSS scores, in which only the subtype of schizophrenia made a statistically significant contribution to predicting mean OSI (F[5,35] = 2.44, P = 0.04). CONCLUSION: Several parameters in the pathogenesis of schizophrenia, such as age of onset, level of negative symptoms, and subtype of illness, but not the presence of the illness itself, are associated with the level of oxidative stress.