"Up to 75% of adults with childhood-onset ADHD exhibit delayed circadian rhythm phase, including a rise in salivary dim-light melatonin onset (DLMO) and alterations in core body temperature and actigraphy-measured sleep-related movements occurring approximately 1.5 hours later in the night than healthy adults. In addition, adults with childhood-onset ADHD exhibit a delay in early morning cortisol rise (i.e., a hypothalamic–pituitary–adrenocortical (HPA) marker of circadian phase), with secretion occurring two hours later than healthy controls. Adults with childhood-onset ADHD are also frequently “night owls” who display delayed circadian preference and increased alertness in the evening (Kooij, 2017, Coogan and McGowan, 2017)."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6487490/
"Up to 75% of adults with childhood-onset ADHD exhibit delayed circadian rhythm phase, including a rise in salivary dim-light melatonin onset (DLMO) and alterations in core body temperature and actigraphy-measured sleep-related movements occurring approximately 1.5 hours later in the night than healthy adults. In addition, adults with childhood-onset ADHD exhibit a delay in early morning cortisol rise (i.e., a hypothalamic–pituitary–adrenocortical (HPA) marker of circadian phase), with secretion occurring two hours later than healthy controls. Adults with childhood-onset ADHD are also frequently “night owls” who display delayed circadian preference and increased alertness in the evening (Kooij, 2017, Coogan and McGowan, 2017)."