• We have previously reported high correlations between norepinephrine and its metabolite outputs in depressed patients. In this article, we expand this finding to healthy volunteers and alcoholic patients. Furthermore, we find similar high correlations between urinary outputs of dopamine, norepinephrine, and their major metabolites. The same is true, to a lesser degree, for epinephrine and metanephrine outputs. There are implications of these findings for psychobiological research on the monoamine systems.