Inconsistent data showed that erythrocyte glutathione peroxidase (GPx) activity in schizophrenics is altered.

The aim of this study was to evaluate whether some of the demographic, clinical and therapeutic factors had any significant impact on erythrocyte GPx activity in patients with schizophrenia.

This study included 68 schizophrenic patients and 59 healthy individuals. GPx activity was tested related to patient age, gender, heredity, the onset of the disease, the duration of the disease, the number of episodes, PANSS scores and drug treatment. GPx activity was determined in erythrocyte hemolysates by Ransel commercially available test.

Erythrocyte GPx activity was significantly lower in patients with schizophrenia than in controls. Male patients had significantly lower GPx activity in comparison with those in female ones. Heredity negative patients showed significantly lower enzyme activity compared to control values. Significantly lower GPx activity was obtained independently of the onset of the disease. The patient group having more than one psychotic episode also showed significantly lower GPx activity compared to the control group. The disease duration of more than 1 year caused a significant decrease in enzyme activity. There was a significant difference in GPx activity between patients with different PANSS scores. In patients treated with second generation antipsychotics and in those treated with both first and second generation antipsychotics, GPx activity was significantly lower than in controls.

This study shows that the low erythrocyte GPx activity in schizophrenics depends on patient gender, the number of episodes, disease duration and drug treatment.

The authors have not supplied their declaration of competing interest.