Jakarta, ThedailyID — Attention Deficit Hyperactivity Disorder (ADHD) is commonly associated with difficulty focusing, impulsivity, and problems managing attention. However, a new study suggests its association may extend to digestive health.
A review involving more than 1.9 million people found that people with ADHD were more likely to experience various gastrointestinal problems. These included constipation, irritable bowel syndrome (IBS), diarrhea, and abdominal pain.
The study was led by researchers from the University of Warwick Medical School. It was published in the Journal of Attention Disorders in September 2026.
Researchers combined data from 23 studies conducted in several countries. These included the United States, Sweden, Germany, China, South Korea, and India.
The participants ranged in age from 2 to 65 years. Overall, people with ADHD were 48 percent more likely to experience gastrointestinal symptoms than those without ADHD.
The association appeared across several digestive conditions. People with ADHD were nearly twice as likely to experience constipation and 58 percent more likely to experience IBS.
The analysis also found that people with ADHD were more than four times as likely to experience encopresis, a condition involving the involuntary passage of stool.
Researchers also found associations between ADHD and diarrhea, abdominal pain, dyspepsia, and other digestive problems.
The researchers have not identified one definitive explanation for the connection. Several factors may play a role, including irregular eating patterns, impulsivity, stress responses, and difficulty recognizing or responding to bodily signals.
ADHD medication may also contribute to some digestive symptoms. Certain stimulant medications can cause side effects such as reduced appetite, stomach pain, nausea, and constipation.
Researchers therefore said medication effects should be distinguished from potential biological mechanisms related to ADHD itself.
Another possibility involves the gut-brain axis, the two-way relationship between the digestive system and the brain. Changes in gut bacteria may interact with the nervous system through several pathways, including the vagus nerve.
However, these mechanisms remain hypotheses that require further research.
The researchers stressed that the study found an association, not causation. The findings do not prove that ADHD directly causes constipation, IBS, diarrhea, or other digestive conditions.
The studies included in the review also differed in their methods and participant characteristics. Some used medical diagnoses, while others relied on reports from participants or parents about digestive symptoms.
The findings therefore suggest that digestive complaints may occur more often among people with ADHD. They may also represent an additional aspect to consider when addressing their overall health.
