Overall Weak Association Between Gastrointestinal Symptoms and Psychological, Autism, and Demographic Variables in Autistic Children

Our study determined psychological, autism trait, somatic, and demographic variables associated with maternal ratings of stomachaches, constipation, diarrhea, and bowel incontinence in autistic children. Mothers of 1,093 autistic children rated their children on the Pediatric Behavior Scale. In regression analyses, the somatic symptom score (i.e., headaches, other aches/pains excluding stomachaches, complains of feeling sick) was the strongest predictor of stomachaches, constipation, and diarrhea. Scores on the other variables (autism severity, externalizing symptoms, internalizing symptoms, autism traits, sleep problems, demographics) each contributed less than 2% more to explained variance. Decreasing age and decreasing IQ were predictors of bowel incontinence. Only 1 of the 30 significant correlations between GI symptoms and the independent variables was large (stomachaches and other somatic symptoms), one was medium (stomachaches and sadness), and four were small to medium (stomachaches and anxiety and increasing age; bowel incontinence and decreasing age and decreasing IQ). The association between GI problems and psychopathology, autism symptoms, and demographics is weak. Findings suggest that researchers and clinicians need to look beyond these variables and consider medical, physiological, neurobiological, and genetic reasons why GI problems are so common in autism relative to children with other neurodevelopmental disorders and neurotypical children.