Background: Schizophrenia is a mental disorder characterized by distortions in thinking, perception, emotions, language, self-sense, and behavior. Recent research suggests that Reactive Oxygen Species (ROS) are involved in the pathophysiology of schizophrenia. Studies have also shown the increased plasma and serum levels of the Trx1 molecule in schizophrenia patients. In the present study, the researchers compared the expression levels of Trx1 mRNA in peripheral blood leukocytes of Iranian schizophrenia patients compared to healthy controls.

Methods: First-episode patients (n=35) who met DSM-IV criteria for schizophrenia were recruited from patients referred to psychiatrists in the city of Ilam and Farabi Hospital in Kermanshah. Healthy people were also selected by recruiting people who, according to a psychiatrist, did not have any mental illness. Diagnoses were made for each patient by two independent experienced psychiatrists and confirmed by the Structured Clinical Interview for DSM-IV (SCID). Patients were treated with risperidone for three months and then compared with thirty- five healthy volunteers. Patients were sampled before and after treatment and then by RNA Extraction and DNA synthesis, Trx1 gene expression was performed by real-time PCR method.

Results: Comparison of Trx1 gene expression in PBMCs of schizophrenic patients before and after treatment with the control group showed that the expression of Trx1 gene of the “before” treatment group was significantly increased compared with that of the control group (P= 0.0007). Also, Trx1 gene expression in PBMCs of “before” and “after “groups showed that Trx1 gene expression of “after” group was significantly decreased compared to the “before” group (P= 0.014). These results showed that the mean of positive, negative, and general psychopathology was reduced significantly in schizophrenic patients before and after treatment in all three cases (P <0.001).

Conclusion: the expression of TRX in PBMCs of schizophrenic patients decreased after risperidone treatment. This reduction of expression was statistically significant and indicates the possible effect of risperidone on the expression of the TRX gene in PBMCs of these patients and decreased gene expression is associated with reduced symptoms. Confirmation of the achievement of this study requires further research.

Key words: Schizophrenia, Thioredoxin, Risperidone