A large new review has strengthened the case for a link between ADHD and gut health, and the finding deserves the attention of every practitioner working with neurodevelopmental presentations. Researchers pooled data from more than 1.9 million people and found that adults and children with ADHD experience considerably more digestive problems than their peers. For South African psychologists, this is a useful reminder that mind and body rarely present in isolation. If you are building your knowledge base this year, our HPCSA-accredited CPD courses cover several adjacent topics in clinical practice.
Furthermore, the study adds weight to a broader idea gaining traction in the research: the gut and the brain are far more connected than we once assumed. Below, we unpack what the review found, why it matters, and how you might apply it in your own practice.
What the ADHD and gut health review found
Researchers at the University of Warwick conducted the first systematic review devoted specifically to gastrointestinal symptoms in ADHD (Blake et al., 2026). Specifically, they combined 23 studies covering more than 1.9 million people across 11 countries. Consequently, the sample size gives the findings real statistical weight.
Overall, people with ADHD had roughly 48% higher odds of gastrointestinal symptoms than people without the condition. Moreover, some individual problems showed even stronger associations. People with ADHD had nearly double the odds of constipation, a 58% increase in irritable bowel syndrome, and more than four times the odds of encopresis, a loss of bowel control (Blake et al., 2026).
Additionally, the pattern held across age groups, from young children to adults. In other words, the association does not appear to be limited to one life stage.
Understanding the gut-brain axis in ADHD
Scientists increasingly describe a “gut-brain axis” that connects digestive health with brain function. Therefore, conditions affecting one system may plausibly influence the other. Digestive problems have already been well documented in autism spectrum disorder, so the ADHD finding fits a wider picture.
Importantly, the researchers are cautious about cause and effect. As lead investigators noted, the data cannot yet confirm that ADHD causes gut problems, or explain exactly what drives the link (Blake et al., 2026). The pattern is nonetheless striking enough to warrant clinical attention.
Several mechanisms remain under investigation. For instance, differences in diet, medication effects, sleep, and stress regulation could all contribute. As a result, the relationship is likely to be complex rather than simple.
What ADHD and gut health means for South African practitioners
For clinicians here, the practical message is straightforward. When a client presents with ADHD, digestive complaints may be more common than expected, and they can affect quality of life. Consequently, it may be worth gently asking about gut symptoms as part of a holistic assessment.
This matters because gut symptoms are easily overlooked when attention is focused on the ADHD itself. Furthermore, unaddressed physical discomfort can compound difficulties with concentration, mood, and daily functioning.
Talking to clients about digestive symptoms
Psychologists are not gastroenterologists, and this evidence does not change that. However, you remain well placed to notice patterns and to encourage appropriate referral. Where digestive symptoms are affecting wellbeing, a conversation with the client’s GP is often the right next step.
In addition, this is an opportunity to reinforce a whole-person view of mental health. Sleep, nutrition, and physical comfort all shape how clients experience their symptoms. Therefore, integrating these threads into your formulation can strengthen your care.
Working within your scope
Always frame physical health observations within your HPCSA scope of practice. Specifically, note the concern, document it, and refer where medical assessment is warranted. This protects both the client and your professional standing.
Limitations of the ADHD and gut health evidence
As with all research, some caveats apply. First, a systematic review pools existing studies rather than collecting new data, so it inherits the strengths and weaknesses of those studies. Second, an association is not proof of causation.
Nevertheless, the scale of this analysis is difficult to ignore. Moreover, it converges with other recent work on how ADHD interacts with the rest of the body and mind, including research on how mind wandering disrupts attention in ADHD. Together, these findings point toward more integrated models of neurodevelopmental care.
Staying current with this kind of evidence is part of responsible, ethical practice. To keep building your clinical toolkit while earning CEUs, explore our 2026 CPD packages designed specifically for South African psychology professionals.
References
- Blake, S., Cannon, H., & Shantikumar, S. (2026). The association between attention-deficit hyperactivity disorder and gastrointestinal symptoms: A systematic review and meta-analysis. Journal of Attention Disorders. Retrieved from https://doi.org/10.1177/10870547261469626
- University of Warwick. (2026, September 11). Study of 1.9 million people finds a striking link between ADHD and gut problems. ScienceDaily. Retrieved from https://www.sciencedaily.com/releases/2026/09/260911003840.htm
- Minamoto, T., Hayashi, T., & Al-Mamun, M. A. (2026). Behavioral and self-report measures of spontaneous mind wandering predict different aspects of ADHD in adults. Journal of Attention Disorders. Retrieved from https://doi.org/10.1177/10870547261448262