Association of serum IL-6 with negative symptoms in stable early-onset schizophrenia

Abstract

Abstract Background: Accumulating evidence suggests that the inflammatory cytokine interleukin-6 (IL-6) contributes to the pathophysiology of psychiatric disorders. The purpose of the current study was to investigate the relationship between serum IL-6 concentration and the clinical features of early-onset schizophrenia (EOS). Methods: We measured serum IL-6 levels from 74 patients with chronic schizophrenia, including 33 with age at onset < 21 years [early-onset schizophrenia (EOS) group] and 41 with onset ≥ 21 years in [adult-onset schizophrenia (AOS) group], and from 41 healthy controls. Symptom severities were evaluated using the Positive and Negative Syndrome Scale (PANSS). Results: Serum IL-6 concentrations were higher in both EOS and AOS groups than healthy controls (F = 22.32, P < 0.01), but did not differ significantly between EOS and AOS groups (P > 0.05) after controlling for age, body mass index, and other covariates. Negative symptom scores were higher in the EOS group than the AOS group (F = 6.199, P = 0.015). Serum IL-6 concentrations in the EOS group were negatively correlated with both total PANSS-negative symptom score (r = -0.389, P = 0.032) and avolition/asociality subscore (r = -0.387, P = 0.026). Conclusion: Patients with early-onset schizophrenia may have more severe negative symptoms than those with adult-onset schizophrenia during the chronic phase of the illness.IL-6 signaling may regulate negative symptoms and its avolition/asociality subsymptoms among the early-onset chronic schizophrenic patients.