On the assumption that neuromelanin content might be a parameter indicating neuronal activity in the catecholaminergic system, neuromelanin was measured microspectro-photometrically in the substantia nigra and the locus ceruleus of 12 brains of patients who had undergone neuroleptic therapy. Neuromelanin increased with age in both regions of 40 control brains. Although no signifícant difference in melanin content between medicated and control brains was seen, a high negative correlation (r = –0.79) was noted in melanin content between the substantia nigra and the locus ceruleus only in each medicated brain, especially in cases of schizophrenia. The possibility of noradrenergic and dopaminergic interaction is discuss