On September 20, the Washington Post reported on how ADHD in some children could be linked to insufficient sleep, far less than the 10-13 hours recommended by the American Academy of Pediatrics for children 3 to 5 years old or the nine to 12 hours recommended for children 6 to 12.
Sandra Kooij, MD, Ph.D. of the Vrije Universiteit Medical Centre in Amsterdam described children and adults with ADHD whose daily cycles of sleep, hormonal activity, temperature, and movement occurred later at night than usual. Evening darkness acts on retinal nerve cells that trigger melatonin secretion by the pea-sized pineal gland in the brain, helping to synchronize the brain's nearby biological clock with the environment. Kooij found that melatonin secretion is delayed in many people with ADHD, sleep onset was delayed as well, sleep duration was insufficient, and inattentiveness could result. She presented these results this September at the annual conference of the European Congress of Neuropsychopharmacology in Paris.
The sleep deficit could also have medical causes leading to interrupted sleep, according to Karen Bonuck, a professor of family and social medicine at Albert Einstein College of Medicine in New York, in her 2012 study of 11,000 children published in the journal Pediatrics. It found that children with interrupted sleep due to snoring, mouth breathing, or other physiological factors were 40 to 100 percent more likely than others to show ADHD-like symptoms by age 7.
The Washington Post article describes enlarged tonsils and adenoids as one cause of disordered sleep which can be amenable to medical treatment. Another cause can be the over-scheduling of activities, over-stimulation by electronic entertainment, artificial light, and the demanding work and commuting schedules of parents that observers see as endemic in many families today. Whether sleep loss is a causal factor for a small or large subgroup of inattentive or hyperactive children is an open question.