Researchers Propose Treating Circadian Rhythm Disruption as a Key Part of ADHD
A perspective article published in Frontiers in Psychiatry in December 2025 reviews evidence that many people with attention-deficit/hyperactivity disorder (ADHD) have a delayed body clock. The authors recommend behavioral measures first, such as fixed wake times and morning light.
A perspective article published in the journal Frontiers in Psychiatry on 10 December 2025 examines the link between attention-deficit/hyperactivity disorder (ADHD) and circadian rhythms, the internal 24-hour clock that regulates bodily processes. The authors pooled existing research and conclude that a substantial share of people with ADHD, though not all, have marked circadian disruption. They suggest that treatment should take this into account, relying mainly on behavioral methods.
What the research shows
According to the data cited, insomnia or sleep disturbances affect up to 80% of adults with ADHD and up to 82% of children with the condition. A delayed sleep-wake cycle occurs in roughly 73–78% of cases. The evening rise of melatonin, the sleep hormone (known as dim-light melatonin onset, or DLMO), comes about 45 minutes later in children and about 90 minutes later in adults compared with people without ADHD. The article also describes blunted and delayed cortisol rhythms, a smaller pineal gland volume and weakened rhythms of the clock genes BMAL1 and PER2.
How the rhythm can be shifted
In studies, melatonin and bright light therapy have moved the rhythm earlier in people with ADHD. In a randomized trial in adults, 0.5 mg of melatonin nightly advanced DLMO by 88 minutes, and ADHD symptoms fell by 14%. In a placebo-controlled trial of 101 children, 3–6 mg of melatonin over four weeks advanced DLMO by 44 minutes, but no changes in behavior or cognitive performance were found within that period. In a three-week trial in adults during autumn and winter, a shift to an earlier circadian preference was the strongest predictor of symptom improvement. In a randomized trial of 244 children, a behavioral sleep program improved ADHD symptoms and sleep six months afterward.
Suggested approach
The authors propose routine screening for sleep and circadian problems, assessment of chronotype, sleep tracking, a fixed wake time, morning bright light and limited evening light, with low-dose melatonin reserved for confirmed or probable delays. They stress that carefully designed trials are needed to measure the effect on core ADHD symptoms.
