Serum creatine phosphokinase levels in patients meeting the St. Louis research diagnostic criteria for schizophrenia.

In this study 18 patients with a research diagnostic criteria diagnosis of schizophrenia had a mean initial serum creatine phosphokinase level significantly higher than that of 36 control subjects with other RDC diagnoses. There were no corresponding elevations in the serum levels of nondrinking alcoholics or patients with primary or secondary affective disorders. The authors suggest that increased creatine phosphokinase levels in schizophrenic patients may be due to a sudden increase in the substance in the dopaminergic or limbic system due to increased muscle membrane permeability or to sympathetic nervous system or adrenergic dominance.