Low blood selenium concentrations in schizophrenic patients on clozapine

Aims To compare plasma and red-cell selenium concentrations of schizophrenic patients treated with clozapine, with healthy controls and patients with mood disorders. Methods Plasma and red-cell selenium concentrations were measured in random venous blood samples from four groups: mood disorder (n=36), schizophrenics treated with clozapine (n=54), schizophrenics not treated with clozapine (n=41) and a healthy control group (n=56). Assays were performed by an independent laboratory that was blinded to the patient groups and specializes in estimating trace metal concentrations. Results Selenium concentrations in plasma and red cells were found to be significantly lower in schizophrenic patients treated with clozapine as compared with all other groups. Conclusions Selenium is an essential antioxidant. Its deficiency has been implicated in myocarditis and cardiomyopathy. Low selenium concentrations in clozapine-treated patients may be important in the pathogenesis of life threatening cardiac side-effects associated with clozapine. Further clinical studies are being conducted to explore this important clinical observation and its therapeutic implications.