Gastrointestinal Symptoms, Behavioural Problems and Restricted Repetitive Behaviours in an Italian Sample of ASD Preschoolers

Background: Gastrointestinal (GI) symptoms in patients with ASD aged 1–18 years have been reported with prevalence higher than in typical development population, ranging from 9% to 91%, depending on the study's characteristics. Moreover, a greater severity of problem behaviours as irritability, emotional dysregulation, anxiety and affective disorders was found in children with ASD and concurrent GI symptoms. In addition, in children with ASD a correlation between GI symptoms and rigid/compulsive behaviours, increased sensory sensitivity, and sleep problems has been suggested. It is worth noting that behaviour problems, and possible self-damaging acts could increase in ASD patients who are not able to communicate their GI discomfort.

Objectives: This study aims to explore if and how the presence of GI symptoms could influence the clinical features of ASD preschoolers and whether it is possible to define a particular clinical phenotype characterized by the presence of GI symptoms and ASD.

Methods: A total of 163 preschoolers with ASD were included in the study, comprising 137 males and 26 females (mean [SD] age = 43.16 [13.85] months; range 20-71 months). ASD patients were assessed through the ADOS, psychometric test, language assessment, Child Behavior Checklist (CBCL 1½-5), and Repetitive Behavior Scale-Revised. CBCL 1½-5 has been used to explore GI symptoms and to identify two groups on the basis of the presence or absence of GI symptoms (“ASD GI+” versus “ASD GI−”).

Results: The percentage of ASD GI+ patients was 40.5%; the more frequently reported symptoms were constipation, feeding problems and abdominal pain. Greater severity of behavioural problems in ASD GI+ children compared to ASD GI- peers was found, whereas differences in ADOS calibrated severity mean scores, in language level and in performance IQ between the two groups were not significant. In ASD GI+ versus ASD GI- patients were detected: (a) more frequent and severe stereotyped behaviours and restricted interests; (b) a more severe dysregulation profile (sum of the scores of the “Anxious/Depressed”, the “Attention Problems” and the “Aggressive Problems” scales of the CBCL); (c) significant higher scores in “Externalized Problems” and “Total Problems” scales of the CBCL (and in lesser proportion also in “Internalized Problems” scale). Moreover, more self-injurious behaviours were observed in subjects with constipation.

Conclusions: We confirm a high prevalence of GI problems in ASD pre-schoolers; in particular, the most common types of GI symptoms in children with ASD were constipation, abdominal pain and significant food problems expressed as resistance to feeding. More frequent behavioural problems were observed in ASD individuals GI+ that could be interpreted as manifestations of a distress difficult to communicate. Crucially, ASD GI+ individuals were not different in language level, cognitive development and autism severity than ASD GI- children. It is therefore useful to investigate the possible presence of GI symptoms in all patients with ASD, even more in children with repetitive and behavioural problems.