Oxidative Stress in Attention Deficit Hyperactivity Disorder Patients

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a mental disorder diagnosed by the symptoms of inattention, hyperactivity and impulsivity when the extent of symptoms impairs the child's ability to function. The underlying pathaetiological basis of ADHD remains unknown. Oxidative stress resulting in cell damage, mainly through the production of reactive oxygen species (ROS), has been implicated in various psychiatric disorders. Byproducts of lipid peroxidation as Malondialdehyde (MDA), transition metals as zinc, and levels of Non-Estrified Fatty Acids (NEFA) can be used as indirect biochemical indicators of oxidative stress. Objective: To elucidate the possible role of oxidative stress in ADHD patients compared with normal controls we assessed different biochemical markers of disrupted oxidative metabolism. Method: We recruited 20 children diagnosed with ADHD using DSM-IV criteria and 16 matched healthy controls. Both were subjected to the Wisconsin Card Sorting Test and patients were further categorized by Conner’s Parent Rating Scale-Revised. Levels of MAD, Zinc, and NEFA were assessed in both groups. Results: There was evidence of increased lipid oxidation with evidence of disturbed lipid peroxidation. The increased MAD level compared with control (94.1±32.2, 39±21.9 p<0.001) was correlated to attention/hyperactivity predominantly inattentive. Additionally zinc levels were decreased compared to control (69±16.9, 95.5±8.8 p<0.001); but the difference was not statistically correlated with any ADHD subtypes. Conclusion: the increased MAD level as a lipid peroxidation marker and the decreased zinc status and their correlation with the inattention profile are in support of the oxidative stress theory in the pathogenesis of ADHD. This may point to the potential implication of antioxidants as a treatment option for ADHD.