INCREASED BRAIN DOPAMINE AND REDUCED GLUTAMIC ACID DECARBOXYLASE AND CHOLINE ACETYL TRANSFERASE ACTIVITY IN SCHIZOPHRENIA AND RELATED PSYCHOSES

Abstract

Dopamine, glutamic acid decarboxylase (G.A.D.) and choline acetyltransferase (C.A.T.) were measured in four regions of post-mortem brains. 41 patients with the hospital diagnosis of schizophrenia (psychotic group) were compared with a control group (n=61). In the psychotic group, dopamine was 48% higher in the nucleus accumbens but normal in the putamen. G.A.D. activity was significantly reduced in the psychotic group, by about 50% in the nucleus accumbens, amygdala and hippocampus, and by about 30% in the putamen. C.A.T. activity was significantly lower in nucleus accumbens from the psychotic group, but normal in other brain regions. From an assessment of case notes, "schizophrenia" was distinguished from "schizophrenia-like psychosis". The biochemical findings for these subgroups were essentially similar, although C.A.T. activity in nucleus accumbens and hippocampus from the schizophrenic group was significantly lower than in controls. It is possible that increased dopamine and reduced G.A.D. and C.A.T. activities in limbic areas of brain are associated with schizophrenia and schizophrenia-like psychoses, although whether such neurochemical abnormalities are related to the illness or are a consequence of prolonged treatment with neuroleptic drugs remains unclear.