A review from University of Warwick researchers suggests that people with ADHD may be more likely to experience digetive problems.
Researchers analyzed 23 studies involving more than 1.9 million people.
Overall, gastrointestinal symptoms were nearly 50% more common among people with ADHD.
Constipation was almost twice as likely, while irritable bowel syndrome was associated with a 58% increase. Encopresis, or loss of bowel control, showed more than four times the odds.
ADHD and the Gut-Brain Connection
Digestive symptoms are already frequently reported in autism.
Scientists have been studying the gut-brain axis, which describes communication between the digestive system and brain.
The Warwick review, published in the Journal of Attention Disorders, specifically examined gastrointestinal symptoms in ADHD.
The studies included participants from the U.S., Sweden, Germany and South Korea, ages 2 to 65.
The review found associations with nearly every digestive symptom examined, including constipation, IBS and general challenges with digestion.
Why Might ADHD Affect Digestion?
There is no clear answer yet. However, impulsivity and irregular eating habits — that are associated with ADHD — could affect digestion.
ADHD medications can also cause gastrointestinal side effects, including constipation.
The gut microbiome is another possibility. Earlier research has found differences in gut bacteria among ADHD’ers.
Those changes could potentially affect communication between the gut and brain through the vagus nerve.
NOTE: The findings do not show that ADHD causes digestive disorders.
They only demonstrate an association. Future research will need to determine whether biological differences, medications, eating patterns or other factors explain the relationship.
