Investigation of the relationship between total oxidant and antioxidant levels with symptom severity, C-reactive protein and metabolic syndrome in patients with schizophrenia

Introduction and Objective: Metabolic syndrome is one of the factors that play a role in the shortened life expectacy of schizophrenia patients compared to general population. The prevalence of metabolic syndrome (MS) in schizophrenia patients is increasing both in our country and in the world. The high prevalence of metabolic syndrome in schizophrenia patients is related to the inflammatory mechanism, antipsychotic drugs, genetics, lifestyle and the disease itself. There are studies investigating the relationship between metabolic syndrome and inflammation and oxidative stress seperately. However, there are no studies comparing metabolic syndrome, oxidative stress and inflammation together in schizophrenia. In this study we aimed to investigate, a) Whether the schizophrenia group and the healthy control group differed in terms of metabolic syndrome parameters, oxidative stress parameters and C-reactive protein (CRP), b) Whether there was any difference in terms of oxidative parameters and C-reactive protein in schizophrenia patients with and without metabolic syndrome, c)Whether there was a relationship between disease severity and oxidative parameters and C-reactive protein in schizophrenic patients. Materials and Methods: 26 drug-free schizophrenia patients (all on acute psychotic episode) and 26 healthy controls matched in terms of age, gender and educational status were compared in regard to metabolic syndrome, oxidative stress parameters and CRP. Positive and Negative Symptom Scale (PANSS) was used for disease severity assesment; while Global Assessment of Functionality Scale (GAF) was used to evaluate functioning and Calgary Schizophrenia Depression Scale (CDSS) was used to exclude depression in schizophrenia patients. Findings and Results: There was a significant difference in TOS (total oxidant status) and OSI (oxidative stress index) between schizophrenia patients and healthy controls; while there was no difference in terms of TAS (total antioxidant status). There was no significant difference between the two groups in terms of CRP levels as well. There was no significant difference in terms of metabolic syndrome prevalence between the two groups, although it was slightly higher in the schizophrenia group. Comparison of the schizophrenia patients with and without metabolic syndrome revealed no significant difference in regard to PANSS, CDSS, TOS, TAS, OSI, CRP, and other clinical variables. TOS correlated positively with duration of hospitalization and number of hospitalizations. A negative correlation was found between OSI and IGD. TOS level was predicted by being a schizophrenia patient and by not having MS. A significant difference was found in terms of TAS, when the schizophrenia and the healthy control groups were divided into four groups according to presence of metabolic syndrome (TAS level was the highest in the healthy control group with metabolic syndrome, followed by the schizophrenia group with metabolic syndrome, then by the schizophrenia group without metabolic syndrome, and then by the healthy control group without metabolic syndrome). TAS level positively correlated with the presence of MS in the whole sample. According to the results of this study, detailed investigation of oxidative stress in the etiopathogenesis of schizophrenia may contribute to prevention of neurodegeneration due to oxidative stress caused by metabolic syndrome leading to a possible increase of lifespan in schizophrenia. Keywords: schizophrenia, oxidative stress, C-reactive protein, metabolic syndrome