Reliability of urinary monoamine and metabolite output measurements in depressed patients.

The authors measured urinary monoamines and their metabolite outputs in 12 unmedicated depressed patients. Output of 3-methoxy-4-hydroxy-phenylglycol and vanillylmandelic acid proved to be relatively stable from one sample to another. An average of at least two measures provided data with a meaningful reliability for normetanephrine, serotonin, and homovanillic acid output. Output of dopamine, norepinephrine, 5-hydroxyindoleacetic acid, and phenylethylamine was highly variable over time.