Kids with autism often struggle with behavior issues, but researchers say a simple new questionnaire may be able to determine if an underlying medical condition is actually the cause.

The 17-item survey is designed to help spot gastrointestinal problems in those on the spectrum.

Individuals with autism are four times more likely than others to have such issues, but may go undiagnosed, researchers say. That’s because many are nonverbal or have sensory difficulties that prevent them from communicating the source of their discomfort.

“Gastrointestinal problems can be painful and disabling and they can have profound effects on a child’s behavior,” said Kara Gross Margolis, a pediatric gastroenterologist and associate professor of pediatrics at the Columbia University Vagelos College of Physicians and Surgeons.

Margolis and her colleagues developed the questionnaire by presenting 131 parents of kids with autism with 35 questions about whether their children gagged during meals, put pressure on their abdomen, arched their back or displayed other signs that might suggest gastrointestinal issues were at play.

All of the children were then assessed by pediatric gastroenterologists who had no knowledge of the parent responses.

Ultimately, the researchers identified 17 questions that were able to distinguish kids with common gastrointestinal problems in 84 percent of cases, according to findings published this week in the Journal of Autism and Developmental Disorders.

Though about a third of children who were flagged by the screening tool did not end up having a gastrointestinal disorder, those behind the study indicated that the questionnaire’s ability to spot more than 80 percent of those who did have a problem means that it’s worthy.

Additional studies of the questionnaire’s validity are underway, researchers said.