Mg⁺⁺ dependent adenosine triphosphatase activity in erythrocyte ghosts of schizophrenic patients

'Membrane' adenosine triphosphatase (ATPase) activity, which was predominantly Mg⁺⁺ dependent ATPase activity, was determined in erythrocyte ghosts from 9 unmedicated schizophrenic patients and controls. Seven of 9 acute and chronic schizophrenic patients had greater 'membrane' red cell ghost ATP activity than their controls. The 'membrane' ATPase activity of both patients and controls was inhibited by ouabain, which differs from patients with various types of muscular dystrophy who have been found in some studies to have increased erythrocyte ghost 'membrane' ATPase activity in the presence of ouabain. Chlorpromazine treatment did not diminish the erythrocyte 'membrane' ATPase activity of 2 schizophrenic patients. Elevated activity of Mg⁺⁺ ATPase in neuronal tissues might affect their excitability and thus have considerable significance for the etiology of psychotic states.