Avcil S - Researchers examined the relations of the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), and mean platelet volume (MPV) with attention-deficit hyperactivity disorder (ADHD). In this study, the ADHD group showed significantly higher NLR, PLR, MLR, MPV, and neutrophil count than the HC group. In the ADHD group, the lymphocyte counts of the patients were significantly lower than those of the HC group. Findings thereby suggest a role of inflammation in the etiopathogenesis of ADHD.