The authors treated 18 rigorously diagnosed depressed patients with
amitriptyline after baseline urine samples were collected for the
measurement of 3-methoxy-4-hydroxphenylglycol (MHPG). Neither age nor
severity of depression before treatment correlated with MHPG excretion.
There was also no significant correlation between baseline MHPG excretion
and clinical response at the end of at least 25 days' treatment with
amitriptyline. The authors discuss the relevance of amitriptyline and
nortriptyline plasma levels to MHPG and the noradrenergic/serotonergic
theories of depression.