Elevated neutrophil-to-lymphocyte ratio in children and adolescents with attention-deficit/hyperactivity disorder.

Our findings suggest that NLR and PLR may be inflammation biomarkers in children and adolescents with ADHD. Moreover, the significance of NLR is not influenced by medication use, age and sex. Prospective studies that address alterations in NLR and PLR and other pro-inflammatory cytokines following ADHD treatment may provide additional information about the inflammatory mechanisms in ADHD.Key pointsThe mean NLR and PLR were significantly higher in patients than in controls.The significance of NLR is not influenced by medication use, age and sex.No associations were found between NLR and PLR and ADHD symptom severity.Prospective studies that address alterations in NLR and PLR and other pro-inflammatory cytokines following psychopharmacological treatment of ADHD may provide additional information about the inflammatory mechanisms in ADHD.