The authors compared a group of boys with childhood autism and a group
of normal boys of similar age and found a decrease in urinary 3-methoxy-
4-hydroxyphenethylene glycol (MHPG) in the autistic group. They hypothesize
that autistic children might have an alteration in central and peripheral
noradrenergic function, which might be related to impaired regulation of
attention, arousal, and anxiety.