Elevated plasma superoxide dismutase in first-episode and drug naive patients with schizophrenia: inverse association with positive symptoms

Prog Neuropsychopharmacol Biol Psychiatry. 2012 Jan 10;36(1):34-8. doi: 10.1016/j.pnpbp.2011.08.018. Epub 2011 Aug 30.


Excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased superoxide dismutase (SOD) activities, a critical enzyme in the detoxification of superoxide radicals. This study compared plasma SOD activities in 78 never-medicated first-episode and 100 medicated chronic schizophrenia patients to 100 healthy control subjects and correlated these SOD activities with the Positive and Negative Syndrome Scale (PANSS) among the schizophrenic patients. We found that both first-episode and chronic patients had significantly increased plasma SOD activities compared to controls, and that chronic schizophrenic patients on antipsychotic medication had significantly higher SOD activities than first episode schizophrenic patients. Plasma SOD activities were also negatively correlated with positive symptoms of schizophrenia, but only in first-episode patients. Thus, oxidative stress appears to be greater in first episode schizophrenic patients with fewer positive symptoms and may become greater as schizophrenia becomes more chronic, although we cannot exclude the possibility that chronic antipsychotic treatment may increase SOD activities and presumed oxidative stress in schizophrenia.

Publication types

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

MeSH terms

  • Adult
  • Biomarkers / blood
  • Enzyme Activation / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Schizophrenia / blood*
  • Schizophrenia / enzymology*
  • Schizophrenic Psychology*
  • Superoxide Dismutase / biosynthesis
  • Superoxide Dismutase / blood*
  • Young Adult


  • Biomarkers
  • Superoxide Dismutase