Strange Bedfellows: The Link between Sleep and Gastrointestinal Problems in Autism

Parents, you weren't imagining it: sleep and gastrointestinal troubles really do occur together in many children with autism. So says a new study that found that children with autism who have poor sleep patterns are twice as likely to have gastrointestinal problems, and vice versa. And more medical problems are linked to more severe behavior problems, the study found.1

Some parents have said that their children's sleepless nights and bowel problems have been viewed as unrelated, behavioral in nature, or perhaps even overblown.2 That is changing, however. "These patterns are not a figment of the families' imaginations. They're real, and let's treat it that way," said a study co-author, Professor Pat Levitt Ph.D., a neurobiologist at University of Southern California.

He and his fellow researchers reached those conclusions after analyzing medical information from two major autism research studies, the Simons Simplex Collection (SSC) and the Autism Genetic Resource Exchange (AGRE). The SSC includes families who have only one child with autism, and AGRE has families with two or more children with autism.

People with autism spectrum disorder (ASD) vary widely in symptoms, abilities and disabilities. The researchers, like many others, want to find a way of categorizing the different types of autism. Scientists have long hoped that if they can find subtypes of autism, they will better understand this complex condition. They also may be able to pinpoint which treatments and therapies work best for each kind of autism, rather than the current system of trial and error. "If everyone were the same, we would figure out one course of action that would help everyone, but it's not that way," he said.

When Dr. Levitt began studying autism in the early 2000s, he said, he was struck by the sizable numbers of children with certain medical problems, such as gastrointestinal disturbances, sleep disorders, or epilepsy. "That was not unusual."

Common GI complaints in Autism

The most common gastrointestinal (GI) complaints in autism are constipation, diarrhea, and gastroesophageal reflux3 (heartburn). GI problems affect from 9 to 70 percent of children with ASD, with autism clinics reporting the higher amount, according to a consensus report in the influential journal Pediatrics.4 One report, by the Autism Treatment Network in 2010, said GI symptoms affect almost half of children with ASD.5

Children with autism are:

At least four times more likely to hospitalized for constipation than other children, according to a study of almost 2.4 million youth ages 3 to 20. Those hospitalizations are nonetheless rare, accounting for just 1.2 percent of the hospital stays in ASD.6

Seven times more likely than typically-developing peers to have had "frequent diarrhea/colitis in the past 12 months."7

In the latest study, Dr. Levitt's research team examined different medical conditions among children with autism to identify patterns. The AGRE project had complete information for the 14 most common medical conditions, such as allergies, abnormal growth, coordination, skin problems, vision problems and gait (walking) abnormalities. The team conducted a statistical analysis of the 14 conditions but did not find any subgroups. "The first question a scientist would ask is, 'Are there patterns with what conditions go together?' And the answer is 'no.' That was disappointing," Dr. Levitt said.

Focusing on a handful of medical conditions in autism

The SSC project did not collect information on all 14 conditions, but it did have data on some of them. The researchers found some patterns when they honed in on three particular conditions described in both the SSC and AGRE projects.

Almost a fourth of the children had both gastrointestinal disturbances and sleep problems. "Sleep disorders and gastrointestinal disorders seemed to travel together," he said. This echoes an earlier study that found sleep problems in about half of the children with autism who have GI problems, compared to only 7 percent of their typically-developing siblings.4, 8

A small but significant percentage of children in the AGRE and SSC project have three conditions – GI, sleep and seizure disorders. That category included 4.5 percent of the AGRE children and 2.6 percent of the SSC youth.

Children with a larger number of medical problems tend to have more severe behavior problems. Why? "It's common sense. If you're ill or in pain, your brain will not perform as well, your attention will be disrupted, and your executive functioning will be affected," Dr. Levitt said.

Finding a link but not a subtype of autism

The study concluded that people with combinations of those three conditions do not represent a subtype of autism. But health care providers treating people with autism should be on the lookout. They should ask about GI problems in children with sleep problems, and vice versa, and consider screening for seizures if they find one or both of the other two disorders, the study said.1

Scientists do not know why a child with ASD would have all three conditions. Problems with sleep, the GI system, and seizures are known to occur in people with two genetic conditions linked to autism: Rett syndrome in girls and fragile X syndrome.

The latest study builds upon previous work by Dr. Levitt and others, including a 2012 study that found that constipation was the most common type of GI problem in children with ASD.9 That study of 122 children found that constipation was not linked to particular eating habits or medications, despite commonly-held assumptions to the contrary.

Those researchers also found a surprising link between constipation, poor expressive speech, and social problems, as well as younger age. "The strong association between constipation and language impairment highlights the need for vigilance by health-care providers to detect and treat [gastrointestinal dysfunction] in children with ASD," their article said.9

"Here's the double-edged sword," Dr. Levitt said in an interview. "If you have a child with little or no expressive language, how can he communicate a gastrointestinal disturbance or express his pain? We think this is really important. If you have a parent who says their child is not sleeping, I would give the parent the Questionnaire on Pediatric Gastrointestinal Symptoms. That helps the clinician get information from parents that will help them determine if their suspicions of a gastrointestinal problem are real."

And they probably are. Parents' hunches about the existence of GI problems were correct more than 90 percent of the time.9 The study "clearly refuted the claim by some physicians that parents may be over-reporting or overly concerned about GI problems in children with autism,"2 according to an article by Autism Speaks, which is affiliated with the Autism Treatment Network clinic where the study took place.

Children with autism and gastrointestinal problems may be different from children who have autism alone, he said. "There may be something that's fundamentally different in what underlies their autism spectrum disorder," he said.

Dr. Levitt worked on a different study, again using AGRE families, that found that some people with autism who have GI problems have a different variation of the MET gene than people with ASD who do not have such problems. The MET gene affects both the brain and GI system.10

Similarly, families in the SSC project played a critical role in the discovery of a very rare subtype of autism that also involves GI problems. People with a mutation to the CHD8 gene share similar facial features, sleep problems, and frequent bouts of constipation followed by loose stools.11

Together, these types of studies have led to greater awareness. "Parents are getting the sense that there is a sea change in the medical and research communities, which are taking these concerns quite seriously," Dr. Levitt said. "We have to do a much better job of understanding this and doing the kind research projects that will be high-yield now, instead of 20 years from now."