Prolidase activity and oxidative stress in patients with schizophrenia: a preliminary study.

Objective: To determine whether serum prolidase levels are associated with the etiopathogenesis of schizophrenia.

Methods: The study was conducted at the psychiatry outpatient clinics of the University Hospitals of Recep Tayyip Erdogan and Afyonkocatepe in spring 2013. It comprised patients with schizophrenia who were consecutively recruited from the Psychiatry outpatient clinics of the hospital. An equal number of healthy individuals were recruited from the community. Each patient underwent a detailed diagnostic evaluation by psychiatry residents by using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-IV. Serum prolidase activity and oxidative parameters were measured in patient and control groups.The severity of psychotic symptoms was assessed using the positive and negative syndrome scale. SPSS 16 was used for statitistical analysis.

Results: There were 30 subjects in each group, with 18 (60%) females among the patients and 21 (70%) among the controls. Serum prolidase level was significantly higher in schizophrenia patients compared to the controls (p < 0.001). Total Oxidative Stress and Oxidative Stress Index parameters were found to be significantly different between the patients and the controls (p = 0.024 and p < 0.001). Serum prolidase level did not show any correlation with markers of oxidative stress in the patients.

Conclusion: Prolidase activity, glutamate transmission and oxidative stress may be inter-related in the etiopathogenesis of schizophrenia.