Elevated Melatonin Levels in Children With Attention Deficit Hyperactivity Disorder: Relationship to Oxidative and Nitrosative Stress.

Objective: The aim of this article is to measure serum antioxidant melatonin, the oxidants of nitric oxide, and malondialdehyde levels to calculate the serum oxidant-antioxidant balance based on the nitric oxide/melatonin and malondialdehyde/melatonin ratios in children with ADHD. Method: The serum melatonin, nitric oxide, malondialdehyde, and the nitric oxide/melatonin and malondialdehyde/melatonin ratios were calculated and compared between the children with ADHD (n = 103) and healthy control participants (n = 73). Results: Serum melatonin and nitric oxide levels were higher, and the nitric oxide/melatonin and malondialdehyde/melatonin ratios were lower in ADHD children than the control group. Melatonin was found to be significantly high, and the malondialdehyde/melatonin ratio was found to be significantly low in children with a positive ADHD family history. Conclusion: The serum oxidant-antioxidant balance was impaired in children with ADHD. Within the ADHD group, higher melatonin levels were determined in the children with a positive family history.