Decreased antioxidant enzymes and membrane essential polyunsaturated fatty acids in schizophrenic and bipolar mood disorder patients

Abstract

Oxidative stress-mediated cell damage has been considered in the pathophysiology of schizophrenia. Abnormal findings have often been considered related to differences in ethnicity, life style, dietary patterns and medications, all of which influence indices of oxidative stress and oxidative cell damage. To minimize these confounds, schizophrenic patients were compared with age-matched control subjects with the same ethnic background and similar lifestyle, as well as with bipolar mood disorder (BMD) patients. Levels of antioxidant defense enzymes (i.e. superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) were lower in schizophrenic patients than in controls, indicating conditions for increased oxidative stress. The contents of plasma thiobarbituric acid reactive substances (TBARS) were only marginally higher in schizophrenic patients, who had normal levels of arachidonic acid (AA), a major source of TBARS, indicating no significant oxidative membrane lipid peroxidation. Levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), however, were significantly lower in schizophrenic patients. When the same indices in BMD patients were compared with findings in matched controls, levels of only SOD and CAT were lower in the patients, whereas GPx was not. Again, as in schizophrenia, the contents of TBARS were marginally higher in BMD patients with no change in levels of AA. Levels of alpha-linolenic acid and EPA were significantly lower and levels of DHA were slightly lower in BMD patients. These data indicate that certain biochemical characteristics may be common to a spectrum of psychiatric disorders, and suggest supplementation of antioxidants and essential fatty acids might affect clinical outcome.