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

BACKGROUND Accumulating evidence suggests that the inflammatory cytokine interleukin-6(IL-6)contributes to the pathophysiology of psychiatric disorders.However,there was no study concerning the relationship between IL-6 concentrations and clinical features in the chronic phase of early-onset schizophrenia(EOS).AIM To investigate the relationship between serum IL-6 concentration and the clinical features of EOS.METHODS We measured serum IL-6 Levels from 74 patients with chronic schizophrenia,including 33 with age at onset<21 years(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 EOS 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.