Serum zonulin and claudin-5 levels in children with attention-deficit/hyperactivity disorder.

These findings provide additional evidence for dysregulation of the blood-brain barrier, especially abnormalities in claudin-5 function, which may be involved in the aetiology of ADHD.Key pointsADHD is one of the most common neurodevelopmental disorders of childhood. Although ADHD is quite common, its aetiology has yet to be fully explained.In recent years, studies on the relationship between intestinal and blood-brain brain barrier permeability and psychiatric disorders have increased.In our study, serum claudin-5 levels were higher in the ADHD group compared to the control group, while serum zonulin levels did not differ between the groups.