Increased repetitive behaviours and prolactin responsivity to oral m-chlorophenylpiperazine in adults with autism spectrum disorders

Sherie Novotny, Eric Hollander, Ann Phillips, Andrea Allen, Stacey Wasserman, Rupa Iyengar

Research output: Contribution to journalArticle

7 Scopus citations


Autism is a neurodevelopmental disorder characterized by dysfunction in three primary behavioural domains: repetitive behaviours, social deficits, and language abnormalities. There is evidence that abnormalities exist in the serotonin (5-HT) system in autism spectrum patients. Furthermore, 5-HT is known to play a role in repetitive and social behaviours. This study examined the effect of m-chlorophenylpiperazine (m-CPP) on repetitive behaviours and prolactin response in 11 adults with autism or Asperger's disorder and 8 age- and gender-matched healthy controls via randomized double-blind, m-CPP and placebo challenges. The primary outcome measure was an instrument rating six repetitive behaviours: need to know, repeating, ordering, need to tell/ask, self-injury, and touching. Patients with autism spectrum disorders showed a significant increase in repetitive behaviours at end-point following oral m-CPP in comparison to placebo. Additionally subjects with autism spectrum disorders showed a significantly increased prolactin response to m-CPP compared to normal controls, with neither group responding to placebo. This study provides further evidence for altered 5-HT sensitivity in individuals with autism spectrum disorders, as well as a possible relationship between repetitive behaviours in autism spectrum disorders and abnormalities in the 5-HT system.

Original languageEnglish (US)
Pages (from-to)249-254
Number of pages6
JournalInternational Journal of Neuropsychopharmacology
Issue number3
Publication statusPublished - Sep 1 2004
Externally publishedYes



  • Asperger's disorder
  • Autism
  • Obsessive-compulsive behaviours
  • Oxytocin
  • Peptide

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health
  • Pharmacology (medical)

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