A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Summer, 2019 | Number 3, Volume 33

Pica may largely explain link between autism, GI problems

Article Body

Pica (the eating of non-food items) may play a significant role in the high rate of gastrointestinal (GI) problems seen in individuals with autism, according to a new study by Dean Alexander and colleagues. The study, using data collected on developmentally disabled clients at the LantermanDevelopmental Center in California, compared four groups of adults:

• Individuals with pica but not autism (16)

•Individuals with autism but not pica (15)

•Individuals with both autism and pica(17)

•A control group of clients matched for gender, age, and level of cognitive functioning (16)

The researchers report, “GI diseases, and signs and symptoms of GI dysfunction, each showed a significant overall effect associated with pica, but not with autism. Those persons diagnosed with pica had 2.8 times as many GI diseases, and 4.8 times as many were severely affected. Persons with pica had 2.6 diseases on average. Additionally, adults with pica showed higher prevalence across all ten most frequently recorded GI diseases.”

They add, “The significant interaction observed in the current study between autism and pica on GI signs and symptoms suggests that it is important to distinguish autism and autism/pica diagnostic groups.” They note that compared to the group with autism alone, the autism/pica group had higher percentages of GERD (35% vs. 7%), vomiting (41% vs27%), abdominal pain (29% vs 0%), constipation (94% vs. 80%), and alternating diarrhea and constipation (29% vs. 7%). 

They conclude, “Our data strongly suggest that the high rate of GI symptoms observed among people with autism can be accounted for by pica…. Indeed, individuals with both autism and pica may be a pheno-typic subgroup.”

The researchers say, “From a behavior-analytic viewpoint, we conceptualize pica here primarily as part of a chain of events:(1) persistent exploratory mouthing of environments (sensory reinforcement), (2) introduction into the gut of harmful bacteria, the metabolites of which may affect the body and brain, (3) maldigestion and malabsorption or faulty metabolism, (4) nutritional deficiencies, (5) pica disorder, (6) GI symptomatology, (7) GI disease.”

The researchers suggest that nutritional deficiencies and imbalance help to set the stage for pica, and recommend that individuals with pica receive nutritional and gastrointestinal evaluation.


“Gastrointestinal tract symptomatology in adults with pica and autism,” Dean D. Alexander, Stanley E. Lunde, and Dale E. Berger, unpublished paper. Address: Dale E. Berger, Department of Psychology, Claremont Graduate University,123 East Eighth Street, Claremont, CA 91711,[email protected].

Editor’s note: While we typically review only published papers, we chose to make an exception in this case because of the importance of these findings.