CDH5 and attention deficit-hyperactivity disorder: Concerning TJs, we detected a significant downregulation of claudin-5, occludin and ZO-1 proteins (39.8 ± 4.6%, 46.7 ± 5.0% and 36.8 ± 8.1% of the control, respectively) in the ADHD model compared to the controls, but no alterations were identified on VE-cadherin levels (Figure 8G).