Neurochemical studies on tardive dyskinesia. II. Urinary methoxyhydroxyphenylglycol and plasma dopamine-beta-hydroxylase.

The noradrenergic correlates 3-methoxy-4-hydroxy-phenylglycol (MHPG) in urine and dopamine-beta-hydroxylase (DBH) in plasma were estimated on 3 consecutive days in chronic schizophrenic patients under neuroleptic treatment, 20 without and 22 with tardive dyskinetic symptomatology. Compared to normals, no differences in DBH activities were found, but MHPG excretion was higher in both patient groups. Dichotomy of DBH and MHPG values according to their medians for the 42 patients revealed a higher incidence of low DBH activities and low MHPG excretion in the tardive dyskinesia group, while there were no differences in relation to low or high actual neuroleptic dose.