Association of Rigid-Compulsive Behavior with Functional Constipation in Autism Spectrum Disorder.

The study measured gastrointestinal symptoms and behavior at one point in time, so it cannot show whether constipation changes behavior or behavior changes constipation. Functional constipation was identified from parent or self report, and the questionnaire used has been shown to underestimate functional constipation compared with a gastroenterologist diagnosis. Behavior was measured by parent report rather than direct observation. Many participants were taking medications that can affect behavior or constipation, and the study could not analyse individual medications or medication classes because children often took more than one. The main compulsive behavior association was not significant in the medication-free subgroup or the behavioral medication subgroup, so the finding may not be consistent when medication status is considered. Only ten participants were minimally verbal, so the study cannot address verbal status well.

This research was supported by a grant to the Autism Treatment Network and Autism Intervention Research Network on Physical Health from the Health Resources Services Administration. Dr. Veenstra-VanderWeele has served on advisory boards for Novartis and Roche Pharmaceuticals and received research funding from Novartis, Roche Pharmaceuticals, Seaside Therapeutics, Forest, Sunovion, and SynapDx. Dr. Beversdorf received research funding from Seaside Therapeutics. The other authors report no conflicts.