Many autistic children suffer from chronic constipation. Gut mobilization was obtained administering polyethylene glycol (PEG) at the dose of 6.9 g/d once a day for 6 months in an open trial involving 21 chronically constipated autistic children 2-8 years old, followed prospectively for 6 months. Children diagnosed with Autism Spectrum Disorder by DSM-5 and confirmed by ADOS-2 criteria, were evaluated before (T0), 1 month (T1), and 6 months (T2) after intestinal mobilization, recording Bristol stool scale scores, urinary p-cresol concentrations, and behavioral scores for social interaction deficits, stereotypic behaviors, anxiety, and hyperactivity.

Chronic constipation is common among children with ASD and is associated with more severe anxiety, hyperactivity, irritability and repetitive behaviors. Young autistic children with chronic constipation display higher urinary and foecal concentrations of p-cresol, an aromatic compound produced by gut bacteria, known to negatively affect brain function. Acute p-cresol administration to BTBR mice enhances anxiety, hyperactivity and stereotypic behaviors, while blunting social interaction. This study was undertaken to prospectively assess the behavioral effects of gut mobilization in young autistic children with chronic constipation, and to verify their correlation with urinary p-cresol. To this aim, 21 chronically constipated autistic children 2-8 years old were evaluated before (T0), 1 month (T1), and 6 months (T2) after intestinal mobilization, recording Bristol stool scale scores, urinary p-cresol concentrations, and behavioral scores for social interaction deficits, stereotypic behaviors, anxiety, and hyperactivity. Gut mobilization was obtained administering PEG (6.9 g/d once a day) for 6 months. A progressive, statistically significant decrease in all behavioral symptoms was recorded over the six-month study period. Urinary p-cresol levels displayed variable trends, mainly increasing at T1 and decreasing at T2. These results support gut mobilization as a simple strategy to at least partly ameliorate ASD symptoms, as well as comorbid anxiety and hyperactivity, in chronically constipated children. These beneficial effects likely involve multiple mechanisms.

Inclusion Criteria:

• Fulfilling DSM-5 diagnostic criteria for Autism Spectrum Disorder
• Chronic constipation, namely unsatisfactory defecation characterized by difficult and infrequent passage of lumpy and hard stools during at least the previous 3 months, as reported by parents based on the Bristol Stool Scale

Exclusion Criteria:

• ASD constipated children already treated with laxatives