Objectives: The aim of this study was to determine the efficacy and tolerability of gastrin-releasing peptide (GRP) for core symptoms of autism spectrum disorder.
Methods: This is a prospective, open-label study with 160 pmol/kg of GRP tested in 10 children with autism. Outcome measures used were the Clinical Global Impressions-Improvement Scale, Aberrant Behavior Checklist (ABC), Childhood Autism Rating Scale, and Autism Diagnostic Interview-Revised. Positive response was defined as a score of 1 (very much improved) or 2 (much improved) on the Clinical Global Impressions-Improvement Scale and an improvement of 25% or greater on at least 1 subscale of ABC.
Results: Six (60%) of the 10 subjects responded to GRP. Improvements were observed on the ABC irritability and hyperactivity subscales in 80% of patients, and 70% exhibited improvement on the social withdrawal subscale. On the Childhood Autism Rating Scale, there was a mean reduction of 4 points (4.3 ± 2.9). Analysis of the Autism Diagnostic Interview-Revised results detected significant improvements in the domain that assesses social interaction, with a mean reduction of 2.4 points (2.4 ± 2.83). Adverse effects occurred in 3 patients.
Conclusions: Gastrin-releasing peptide was safe and well tolerated by most subjects and may be effective for core symptoms of autism.