Lower plasma tumor necrosis factor-α is associated with symptomatic remission in patients with schizophrenia.

We investigated the plasma tumor necrosis factor (TNF)-α levels between patients with schizophrenia remission and healthy controls, and the association between the plasma TNF-α levels and cognitive function and social function. This cross-sectional study included 48 patients with schizophrenia who fulfilled the remission criteria and 20 healthy controls. Plasma TNF-α levels were measured using the enzyme-linked immunosorbent assay, and cognitive function was assessed using the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS-J). We measured social function using the Social Functioning Scale (SFS-J). The plasma TNF-α levels were significantly lower in the remission schizophrenia group (31.7 ± 27.4 ng/mL) compared to the heathy control group (55.1 ± 38.5 ng/mL) (P = 0.01). In contrast, no correlation was observed between the plasma levels of TNF-α and all BACS-J scores and all SFS-J scores in either group. This result suggests that plasma TNF-α levels may serve as a clinical biomarker of remission of schizophrenia and that the plasma TNF-α levels bore no association with cognitive function. Thus, TNF-α may have potential as a useful indicator of the therapeutic response in patients with schizophrenia.