Complex Link Exists Between ADHD and IBS, Gastric Reflux, Ulcers: New Research

July 22, 2025ADHD and post-traumatic stress disorder (PTSD) may cause several common gastrointestinal diseases, and individuals with ADHD are 63% more likely to develop irritable bowel syndrome (IBS) than their neurotypical peers, according to new genetic research1 and a meta-analysis.2 Together, these two studies shed light on the multi-layered relationship between ADHD and common gastrointestinal disorders such as reflux, gastritis, and IBS, offering support for the growing awareness of gut health’s influence on ADHD symptoms.The first study, published in Medicine, sought to determine whether a causal relationship exists between gastrointestinal diseases and ADHD as well as PTSD.

Researchers performed a Mendelian randomization analysis using data from the FinnGen study related to 24 gastrointestinal diseases, and data from the Psychiatric Genomics Consortium related to ADHD and PTSD.Researchers found that genetic susceptibility to ADHD was linked to:Genetic susceptibility to PTSD was linked to:This data, concluded the study authors, “provides evidence supporting causal relationship between PTSD and ADHD with specific gastrointestinal diseases.”A second study, published in Scientific Reports, investigated the association between ADHD and intestinal disorders.

The large-scale meta-analysis analyzed 11 studies conducted on 3.8 million people from four continents, including more than 175,000 with an ADHD diagnosis.

Researchers explored associations with nine intestinal disorders, including irritable bowel disease (IBD), IBS, celiac disease, peptic ulcers, and recurrent abdominal pain.Individuals with ADHD were found to be 63% more likely to have IBS than their neurotypical peers.