Gastrointestinal disease is very common in children with autism spectrum disorders. They frequently have complaints such as diarrhea, constipation, abdominal pain, abdominal distension, reflux, and flatulence. Evaluation of these children should proceed in the same manner as it would if the child did not have autism. The majority of these children will ultimately be found to have lesions in either the small or large intestine, or both. These lesions take the form of ulcerations, erosions, pathologic lymphoid nodular hyperplasia (LNH), and enterocolitis.

While the underlying cause of these lesions is still unknown, they do seem to represent an autoimmune response inappropriately directed against the gastrointestinal mucosa, which is the lining of the GI tract. A leading conceptual model linking the gastrointestinal pathology to the cognitive deficits involves a biochemical sequence of events in which luminal contents (consisting primarily of ingested foodstuffs) is pathologically absorbed through the highly permeable inflamed intestinal mucosa before having a chance to be broken intraluminally into smaller micromolecules. The absorbed macromolecules then undergo metabolic degradation and processing by pathways not normally employed, resulting in the production of byproducts that may be toxic to the developing brain. Though ultimately theoretical, this proposed mechanism is supported in its separate steps, both by published scientific data and the observations of clinicians caring for these children.

At Thoughtful House we find that when we treat a child's underlying health issues, their autistic behaviors improve or even disappear completely.