Patterns of Lateral Frontal Delta Asymmetry in Adult Attention-deficit/Hyperactivity Disorder with Comorbid Depression: A Quantitative Electroencephalography Study

Objective: Attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood and is frequently comorbid with depression, complicating diagnosis and treatment. Quantitative electroencephalography (qEEG) may aid in distinguishing ADHD alone from ADHD with depression by identifying neurophysiological markers. Methods: This retrospective study included 45 adults with ADHD, 24 with comorbid depression and 21 without. Diagnoses were confirmed through structured Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition-based interviews and neuropsychological testing. Resting-state EEGs were recorded with 19 electrodes under eyes-closed conditions. Data underwent artifact rejection and independent component analysis, and spectral power was calculated for delta, theta, alpha, beta, high beta, and gamma bands. Frontal regions and asymmetry indices (Fp2-Fp1, F4-F3, and F8-F7) were analyzed using ranked ANCOVA, adjusting for age, sex, Full-Scale IQ, and current medication status. Results: = 0.051). Conclusion: In this pilot study, adults with ADHD with and without comorbid depression showed distinct patterns of frontal delta asymmetry, suggesting that depressive comorbidity may be associated with variability in qEEG features. Further well-powered, longitudinal studies are needed to determine the clinical utility of qEEG as an adjunctive tool in ADHD.