Serum HMGB1 levels were significantly higher in the ADHD group(967.5 ± 462.0 ng/mL) than in the control group(693.4 ± 366.9 ng/mL), with p = 0.003, suggesting a potential rolefor chronic low-grade inflammation in the pathophysiology of adult ADHD. This evidence concerns the gene HMGB1 and attention deficit-hyperactivity disorder.