Elevated interleukin-18 serum levels in chronic schizophrenia: Association with psychopathology

J Psychiatr Res. 2012 Aug;46(8):1093-8. doi: 10.1016/j.jpsychires.2012.04.026. Epub 2012 May 28.


Background: Schizophrenia is associated with various abnormalities in the immune system including elevated levels of Interleukin-18 (IL-18), a potent inflammatory cytokine in T-helper 1 (Th1) responses. The aim of this study was to assess the clinical significance of serum IL-18 levels in various stages of schizophrenia.

Methods: We measured serum IL-18 levels using a sandwich enzyme-linked immunosorbent assay (ELISA) from 78 never-medicated first-episode schizophrenia, 79 medicated chronic schizophrenia and 78 healthy control subjects. The symptoms of schizophrenia were assessed by the Positive and Negative Syndrome Scale (PANSS).

Results: The chronic patients had significantly greater serum IL-18 levels than both first-episode patients and controls. Serum IL-18 was also positively correlated with the PANSS general psychopathology subscore in chronic schizophrenic patients.

Conclusions: Our results showed elevated IL-18 pathway activity may be involved in the psychopathology of schizophrenia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Antipsychotic Agents / therapeutic use
  • Chronic Disease
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Interleukin-18 / blood*
  • Male
  • Psychiatric Status Rating Scales
  • Schizophrenia / blood*
  • Schizophrenia / drug therapy
  • Schizophrenic Psychology*
  • Statistics as Topic
  • Young Adult


  • Antipsychotic Agents
  • Interleukin-18