Comparative Effectiveness of Eicosapentaenoic Acid (EPA) versus Docosahexaenoic Acid (DHA) in Reducing Attention-Deficit/Hyperactivity Disorder (ADHD) Symptoms: A Systematic Review

Introduction: Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder in children, characterized by developmentally inappropriate inattention, impulsivity, and hyperactivity, leading to impaired academic and social functioning. Some evidence suggests that children with ADHD may have lower levels of omega-3 fatty acids, particularly EPA and DHA. However, it remains unclear whether either EPA or DHA is more effective in improving ADHD-related symptoms.Objective: To compare the effectiveness of Eicosapentaenoic Acid (EPA) versus Docosahexaenoic Acid (DHA) supplementation in children with ADHD.Methods: We searched PubMed, ScienceDirect, and Google Scholar using relevant keywords. After primary and secondary screening, only two randomized trials met the inclusion criteria. Data were extracted on ADHD symptom outcomes (Conners’ Parent Rating Scales), literacy and cognitive performance, erythrocyte fatty acid levels, and subgroup analyses such as children with learning difficulties. Study quality was assessed, focusing on design, outcome measures, biomarker associations, and limitations including small sample size, dropout rates, and crossover effects.Results: Neither trial demonstrated a significant difference between EPA and DHA supplementation in improving overall ADHD symptoms or literacy outcomes. However, increases in erythrocyte omega-3 levels—particularly DHA—were associated with better cognitive and behavioral outcomes. In one trial, increased RBC DHA significantly correlated with improved word reading (p < 0.01) and reduced oppositional behavior (p < 0.01). In another crossover trial, combined RBC EPA and DHA increases were significantly associated with improvements in spelling (r = 0.365, p < 0.001), attention (r = −0.540, p < 0.001), hyperactivity (r = −0.310, p < 0.001), and related behavioral measures.Conclusions: Current evidence does not support a clear superiority of EPA over DHA or vice versa in treating ADHD symptoms in children. However, overall increases in omega-3 levels—particularly DHA—appear beneficial. Larger, well-designed studies are needed to clarify their independent effects.