Prevalence of chronic gastrointestinal symptoms in children with autism and autistic spectrum disorders.

The team mailed short surveys to parents in the Midwest. They asked about stomach pain, diarrhea, and constipation in kids with autism.

One hundred thirty-seven surveys came back. The study counted how many kids had each gut problem.

One in four children had chronic GI trouble. Diarrhea was the top complaint at 17%.

Kids who had lost skills did not have more gut issues than kids who had not.

Kang et al. (2014) later saw 50% GI complaints in a clinic sample. The jump from 24% to 50% shows hospital families report more problems than mail-in families.

Slaughter et al. (2014) added typically developing peers. They found kids with autism had far more gut pain, and that pain went hand-in-hand with irritability and stereotypy.

Johnson et al. (2009) pooled 144 studies and saw GI rates from 4% to 97%. The wide range makes the 24% in the 2003 paper look modest, but both point to the same takeaway: ask about the belly every time.

You already track tantrums and sleep. Add two gut questions to your intake: "Any diarrhea, constipation, or belly pain weekly?" If the answer is yes, talk to the pediatrician and watch for behavior spikes after meals. Treating GI discomfort can cut problem behavior before you start formal interventions.