The relationship between repetitive behaviors and growth hormone response to sumatriptan challenge in adult autistic disorder

Autism is heterogeneous with respect to clinical symptoms and etiology. To sort out this heterogeneity in autism, we investigated whether specific neu robiological markers vary in parallel to cove symptomatology. Specifically, we assessed growth hormone response to the 5-HT Id agonist, sumatriptan, a nd linked this measure of serotonergic function to the severity of repetiti ve behaviors in adult autistic patients. Eleven adult patients with autism or Asperger's disorder were randomized to single dose sumatriptan (6 mg SQ) and placebo challenges, separated by a one-week interval. In adult autisti c disorders, severity of repetitive behaviors at baseline, as measured by Y BOCS-compulsion score, significantly positively correlated with both peak d elta growth hormone response and area under the curve growth hormone respon se to sumatriptan. Thus, the severity of a specific behavioral dimension in autism (repetitive behaviors) parallels the sensitivity of the 5-HT Id rec eptor,. as manifest by sumatriptan elicited GH response. (C)1999 American C ollege of Neuropsychopharmacology. Published by Elsevier Science Inc.