Serum zonulin levels are correlated with symptom severity independent from body mass index and gender in children with attention deficit hyperactivity disorder

Objective: It has been recently emphasized that neurodevelopmental disorders such as schizophrenia, autism spectrum disorder and attention deficit hyperactivity disorder (ADHD) may be related to the gut-brain axis. Zonulin is a protein that changes the integrity of tight junctions between gastrointestinal mucosa cells. We aimed to investigate serum zonulin levels and its relationship with symptom severity in children with ADHD. Method: 21 ADHD patients and 19 controls were included. Zonulin levels were obtained from blood specimens. Clinical severity of the ADHD symptoms was evaluated by Conner's Parents Rating Scale-Revised/Long Form (CPRS-R/L) and Conner's Teacher Rating Scale-Revised/Long Form (CTRS-R/L) in ADHD group. Results: There was no significant difference between the groups in terms of age, gender and body mass index. Mean serum zonulin level of the ADHD group was 13.45 +/- 9.08 and 21.32 +/- 19.96 in the control group. There was no significant difference between groups (t=1.99, p=0.51). Significant correlation was found (R=0.82, p<0.01) between serum zonulin levels and CTRS-R/L scores in the ADHD group. This correlation persisted when BMI and sex variables were controlled (R=0.85, p<0.01). Discussion: We have found significant correlation between ADHD symptom severity and serum zonulin levels, whereas there was no significant difference between children with ADHD and controls.