Increased interleukin-6 level in Taiwanese schizophrenic patients.

Background: Schizophrenia is accompanied by an activation of the immune/inflammatory system. In the present study, the relationships between serum interleukin (IL)-6, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β1 levels and schizophrenia were explored in a group of Taiwanese inpatients. Furthermore, the serum IL-6, TNF-α, and TGF-β1 levels of patients with schizophrenia were compared before and after 1 month of antipsychotic treatment.

Methods: The serum IL-6, TNF-α, and TGF-β1 levels of 34 acute stage schizophrenic patients and 30 healthy control subjects were collected. These levels were again collected in the 34 patients after 1 month of antipsychotic treatment. An analysis of covariance (ANCOVA) adjusted for gender was performed to examine the differences in cytokine levels between the schizophrenic patients and the control group. Repeated measures ANCOVA adjusted for gender was performed to examine the differences in cytokine levels of the schizophrenic patients before and after 1 month of treatment.

Results: Using ANCOVA adjusted for gender, significantly increased IL-6 levels were found in schizophrenic patients compared with the control group (p = 0.02), but there were no significant differences in TNF-α and TGF-β1 levels (p = 0.06 and 0.91, respectively). After 1 month of medical treatment, there were no significant differences in IL-6 (p = 0.64), TNF-α (p = 0.48), and TGF-β1 (p = 0.23) levels in the schizophrenic patients, although IL-6 appeared to be normalizing.

Conclusion: An increase in the IL-6 level may play a role in the pathophysiology of schizophrenia. A larger sample size and a longer period of follow-up are needed to confirm this finding.