Study of the Nutritional, Inflammatory, and Metabolic Endophenotypes of Attention-Deficit/Hyperactivity Disorder (ADHD)

This study aims to better understand the biological mechanisms involved in attention deficit hyperactivity disorder (ADHD) and to clarify why some children and adolescents respond well to methylphenidate (MPH)-the most commonly prescribed medication-while others do not. Although MPH is effective for many patients, a significant number experience limited benefits or problematic side effects such as appetite loss and sleep difficulties. Recent research suggests that inflammation and oxidative stress in the body may play an important role in ADHD. Some animal studies also indicate that MPH itself might trigger inflammatory processes, but this has never been examined directly in humans. The main goal of this research is to determine whether children with ADHD show differences in their nutritional, immune, and inflammatory profiles compared to children without ADHD, and whether these biological factors influence symptom severity, digestive problems, and response to treatment. The study also seeks to understand whether MPH has a measurable inflammatory effect in young patients and whether this could be linked to treatment tolerability. To answer these questions, the study combines several approaches. First, a case-control comparison will examine differences between children/adolescents with ADHD and age- and sex-matched controls. Second, a one-year follow-up of the ADHD group will evaluate changes over time and help identify biological predictors of treatment response and side effects. Finally, a cross-sectional analysis will investigate the role of polyphenols-natural antioxidant compounds found in food-in relation to inflammation, treatment outcomes, and gender differences. The primary focus is on comparing levels of the inflammatory marker IL-6 between children with ADHD and controls. Secondary objectives include assessing additional inflammatory and immune indicators, nutritional status, gastrointestinal symptoms, ADHD severity, irritability, and MPH tolerability.