Drug-treated children should be included in further research to compare NLR and Claudin-5 before and after treatment; also, the BBB integrity and neutrophil correlation should be confirmed by both laboratory and imaging studies in future studies, and the role of increasing neutrophil levels should be investigated thoroughly if it can be a modality for the treatment of severe cases of ADHD, also, the use of cytokines in future researches concerning inflammatory cells and Claudin-5 should be considered. Here, CLDN5 is linked to attention deficit-hyperactivity disorder.