Growth hormone response to guanfacine in boys with attention deficit hyperactivity disorder: a preliminary study.

OBJECTIVE

This preliminary study evaluated a method for assessing central noradrenergic function in children via the growth hormone response to a single dose of the alpha-2 adrenergic receptor agonist guanfacine and examined whether this measure distinguishes between attention deficit hyperactivity disorder (ADHD) boys with and without reading disabilities (RD).

METHODS

Plasma growth hormone was assessed before and after the oral administration of guanfacine and placebo in boys with ADHD who were divided into subgroups based on the presence (n = 3) or absence (n = 5) of RD.

RESULTS

Guanfacine and placebo conditions did not differ at baseline, but peak growth hormone was significantly higher following guanfacine. The increase in growth hormone following guanfacine was significantly greater in boys without RD as compared to those with RD, with no overlap between the groups.

CONCLUSIONS

Consistent with findings using peripheral measures of noradrenergic function, these preliminary data suggest that ADHD boys with and without RD may differ in central noradrenergic function.