A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Winter 2024 | Number 1, Volume 38

Multi-site study finds that pancreatic enzyme replacement therapy may aid children with ASD

A new multi-center study suggests that pancreatic enzyme replacement therapy may reduce behavior problems in young children with autism spectrum disorders (ASD).

Deborah Pearson and colleagues say research indicates that 65% of children with ASD have deficient levels of chymotrypsin enzyme activity. Chymotrypsin, an enzyme produced by the pancreas, helps to break down proteins into amino acids. A deficiency of chymotrypsin, the researchers say, can result in a lowered pool of essential amino acids including tryptophan (needed to produce serotonin) and phenylalanine (needed to produce dopamine). This, in turn, can affect behavioral and cognitive function.

To study the effects of supplementation with pancreatic enzymes, the researchers enrolled 190 children with ASD, all between three and six years of age, at 32 clinical sites around the United States. The first phase of the study was double-blinded and lasted for 12 weeks. In this phase, 92 of the children received the enzyme supplement in 900 mg doses sprinkled on their food three times a day, while 98 received a placebo. In the second 24-week phase, which was nonblinded, all of the children took the supplement for 24 weeks.

In the first phase, compared to parents of children in the placebo group, parents of children in the treatment group reported that their children exhibited significantly less irritability, hyperactivity, noncompliance, and inappropriate speech. At the end of the 24-week phase, parents reported significant decreases in all of these behaviors as well as in lethargy and social withdrawal.

Pearson concludes, “This study demonstrated that pancreatic enzymatic replacement—which is thought to enhance the supply of essential amino acids necessary for the synthesis of neurotransmitters—was associated with improved behavioral function in preschoolers with ASD, with minimal side effects.”


“Pancreatic replacement therapy for maladaptive behaviors in preschool children with autism spectrum disorder,” Deborah A. Pearson, Robert L. Hendren, Matthew F. Heil, William R. McIntyre, and Shane R. Raines, JAMA Network Open, November 30, 2023 (free online). Address: Deborah A. Pearson, Faillace Department of Psychiatry & Behavioral Sciences, McGovern Medical School, 1941 E Rd., Room 3.126 BBSB, Houston, TX 77054, [email protected].


“Pancreatic enzymatic replacement therapy improves maladaptive behavior in preschool children with autism, finds study,” news release, Halle Jones, University of Texas Health Science Center at Houston, December 18, 2023.