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ADHD as a circadian rhythm disorder: evidence and implications for chronotherapy

Luu B, Fabiano N

Frontiers in psychiatry, 2025

90 participants · 12 citations

Abstract

Accumulating evidence indicates that circadian rhythm dysfunction is a clinically significant and highly prevalent phenotype in a substantial subgroup of individuals with Attention-Deficit/Hyperactivity Disorder (ADHD). This perspective synthesizes convergent lines of evidence demonstrating strong associations between ADHD and evening chronotype with phase-delayed biological markers. Sleep disturbances are profound: insomnia and sleep disturbances affect up to 80% of adults with ADHD and similarly up to 82% of children with ADHD, delayed sleep-wake timing occurs in up to 78%, and dim-light melatonin onset (DLMO) is delayed by approximately 45 minutes in children and 90 minutes in adults. These alterations coincide with blunted and delayed cortisol rhythms, reduced pineal volume, and attenuated peripheral clock-gene rhythms (BMAL1/PER2). Intervention studies demonstrate that the circadian phase can be successfully advanced in ADHD populations. Melatonin and bright light therapy has advanced DLMO in both children and adults with ADHD. Emerging data correlate phase advancement with ADHD symptom improvement, and winter trials suggest circadian preference shifts best predict symptom improvement. Sleep programs improve ADHD symptoms, sleep quality, and functioning in children. Exercise and multimodal protocols for evening chronotypes successfully advance circadian timing in non-ADHD populations and warrant investigation in ADHD. Based on this evidence, we propose a pragmatic,…

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