Increased growth hormone response to sumatriptan challenge in adult autistic disorders

Serotonergic (5-HT) abnormalities have been documented in autism. To assess sensitivity of the 5-HT1d receptor, growth hormone response to the 5-HT1d receptor agonist sumatriptan was studied in adult autistic patients and mat ched normal controls. In this study, 11 adult patients with autism or Asper ger's disorder were compared with nine matched controls. All subjects were randomized to single dose sumatriptan (6 mg SQ) and placebo challenges, sep arated by a 1-week interval, and growth hormone was measured before and dur ing the challenges. The results showed a highly significant diagnosis x dru g x time interaction on repeated measure analysis covaried for baseline. Th is suggests that autistic patients had significantly greater growth hormone response to sumatriptan than normal controls, independent of placebo effec ts. Therefore, abnormalities in 5-HT regulation in autism may be related to increased sensitivity of the 5-HT1d inhibitory receptor in autism. (C) 200 0 Elsevier Science Ireland Ltd. All rights reserved.