URINARY CATECHOLAMINE EXCRETION AND BEHAVIORAL-DIFFERENCES IN ADHD AND NORMAL BOYS

Urinary catecholamine excretion was assessed in 15 boys with attention -deficit/hyperactivity disorder (ADHD) and 16 normal controls during a defined physical and mental task. Dihydroxyphenylalanine, dopamine, n orepinephrine (NE), epinephrine (EPI), 3,4-dihydroxyphenylacetic acid, and 3,4-dihydroxyphenylglycol (DOPEG) concentrations were assayed by high-pressure liquid chromatography with electrochemical detection. Th e urinary concentration of DOPEG, an NE metabolite that has not been p reviously measured in ADHD, was significantly lower in the ADHD subjec ts than in the normal controls. There was also a trend for lower urina ry EPI levels in the hyperactive boys. Stepwise multiple regression an alyses demonstrated that DOPEG and EPI each contributed significantly to the variance in the behavioral symptoms within the full sample. The results are consistent with previous reports of abnormal metabolism o f norepinephrine and epinephrine in ADHD. These neurochemical findings may be due to differences between ADHD and normal boys in neuronal (c entral or peripheral) or nonneuronal (e.g., adrenal, renal) activity. The results are also consistent with prior findings in normal children of an inverse relationship between EPI excretion and inattentive, res tless behaviors. Together, these findings suggest caution in ascribing metabolite changes to ADHD or to ADHD-like behaviors that may be seen in normal children.