Illustration showing the gut-brain connection in a child with ADHD.

Is There a Gut-Brain Connection in ADHD? New Research Explores the Link

Rhea Morgan in Health & Wellness December 2025 • 4 min read.

"Could zonulin, a protein linked to intestinal permeability, be a key factor in hyperactivity and social difficulties?"

Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition affecting children worldwide. Characterized by inattention, hyperactivity, and impulsivity, ADHD can significantly impact academic performance and social interactions. While the exact causes of ADHD remain a subject of ongoing research, scientists are increasingly exploring the role of the gut-brain axis.

The gut-brain axis refers to the bidirectional communication network between the gastrointestinal tract and the brain. This complex system involves various pathways, including the vagus nerve, the immune system, and the production of neurotransmitters. Emerging evidence suggests that disruptions in the gut microbiome and increased intestinal permeability may play a role in the development and severity of neurodevelopmental disorders, including ADHD.

A recent study published in Comprehensive Psychiatry has shed light on the potential link between increased zonulin levels, a marker of intestinal permeability, and ADHD symptoms in children. This research delves into the relationship between gut health and the core features of ADHD, offering new avenues for understanding and potentially managing this complex condition.

Zonulin: The Key Player in Gut Permeability and ADHD?

Illustration showing the gut-brain connection in a child with ADHD.

The study, led by Gonca Özyurt and colleagues, involved 40 children diagnosed with ADHD and a control group of 41 healthy children. Researchers measured zonulin levels in the participants' blood and assessed ADHD symptoms using the DuPaul ADHD scale. Social functioning was evaluated using the Social Responsiveness Scale (SRS).

The results revealed that children with ADHD had significantly higher serum zonulin levels compared to the control group. They also exhibited greater impairment in social functioning. Further analysis indicated a direct correlation between zonulin levels and hyperactivity symptoms, as well as social responsiveness scores.

Higher Zonulin Levels: Children with ADHD showed elevated zonulin levels.
Impaired Social Functioning: The ADHD group experienced greater difficulties in social interactions.
Correlation with Hyperactivity: Zonulin levels were linked to hyperactivity symptoms and social responsiveness scores.

These findings suggest that increased intestinal permeability, as indicated by elevated zonulin levels, may be associated with more pronounced hyperactivity and social difficulties in children with ADHD. The researchers propose that zonulin's role in regulating tight junctions in the gut and blood-brain barriers could be a contributing factor. Disruptions in these barriers may allow substances to leak into the bloodstream, potentially affecting brain function and contributing to ADHD symptoms.

What Does This Mean for ADHD Management?

While this study provides valuable insights into the potential role of gut health in ADHD, further research is needed to fully understand the complex interplay between zonulin, intestinal permeability, and ADHD symptoms. Future studies should investigate the gut microbiota composition in children with ADHD, explore the impact of dietary interventions, and examine the potential benefits of targeted therapies aimed at improving gut health.

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This article is based on research published under:

DOI-LINK: 10.1016/j.comppsych.2018.10.006, Alternate LINK

Title: Increased Zonulin Is Associated With Hyperactivity And Social Dysfunctions In Children With Attention Deficit Hyperactivity Disorder

Subject: Psychiatry and Mental health

Journal: Comprehensive Psychiatry

Publisher: Elsevier BV

Authors: Gonca Özyurt, Yusuf Öztürk, Yeliz Çağan Appak, Fatma Demet Arslan, Maşallah Baran, İnanç Karakoyun, Ali Evren Tufan, Aynur Akay Pekcanlar

Published: 2018-11-01

Everything You Need To Know

What is ADHD, and what are its main characteristics?

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition characterized by inattention, hyperactivity, and impulsivity. These symptoms can significantly affect a child's academic performance and social interactions. The exact causes of ADHD are still being researched, but the connection between the gut-brain axis, including the role of the gut microbiome and increased intestinal permeability, is becoming increasingly important in understanding this condition.

What is the gut-brain axis, and why is it relevant to understanding ADHD?

The gut-brain axis is a complex communication network that connects the gastrointestinal tract and the brain. It involves pathways such as the vagus nerve, the immune system, and neurotransmitter production. Disruptions within this axis, including issues with the gut microbiome and increased intestinal permeability, are thought to contribute to the development and severity of neurodevelopmental disorders, including ADHD. This connection highlights how gut health may influence brain function and behavior.

What is zonulin, and how is it related to ADHD?

Zonulin is a protein that is linked to intestinal permeability. High levels of zonulin can indicate a 'leaky gut,' where the intestinal lining becomes more permeable. This can allow substances to leak into the bloodstream. In the context of the study, higher zonulin levels in children with ADHD were found to correlate with hyperactivity symptoms and social difficulties. The role of Zonulin is significant as it may affect the blood-brain barrier, potentially impacting brain function and contributing to ADHD symptoms.

What were the key findings of the study regarding zonulin and ADHD?

The study measured zonulin levels in children diagnosed with ADHD and a control group. The results showed that children with ADHD had significantly higher serum zonulin levels and experienced greater impairment in social functioning compared to the control group. There was also a direct correlation between zonulin levels and hyperactivity symptoms. This suggests that increased intestinal permeability, as indicated by elevated zonulin levels, may be associated with more pronounced hyperactivity and social difficulties in children with ADHD.

What are the implications of this study for ADHD management and future research?

The findings suggest that there could be a link between gut health and ADHD symptoms, specifically, elevated zonulin levels, a marker of intestinal permeability, were associated with more pronounced hyperactivity and social difficulties. Further research is needed to understand the relationship between zonulin, intestinal permeability, and ADHD symptoms. Future studies should investigate the gut microbiota composition, explore dietary interventions, and examine targeted therapies that aim to improve gut health, potentially offering new ways to manage ADHD.