Plasma amine metabolites before and after withdrawal from neuroleptic treatment in chronic schizophrenic inpatients.

Plasma catecholamine metabolites were measured in paired blood samples from 22 subjects with chronic schizophrenia. One sample was drawn while patients were on a stable dose of neuroleptic medication; the second was drawn 6 weeks after discontinuation of medication. In comparison with baseline values during neuroleptic treatment, there was a significant increase in the plasma concentration of the norepinephrine metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG), and a trend toward an increase in the plasma concentration of the dopamine metabolite, homovanillic acid (HVA), in the medication-free subjects. There were no significant correlations between plasma MHPG or HVA concentrations and the corresponding ratings of psychopathology for these patients.