PARIS – Converging evidence suggests that attention-deficit/hyperactivity disorder and sleep difficulties share a common underlying etiology involving circadian rhythm disturbance, J.J. Sandra Kooij, MD, PhD, declared at the annual congress of the European College of Neuropsychopharmacology.
“If you review the evidence, it looks more and more like ADHD and sleeplessness are two sides of the same physiological and mental coin,” said Dr. Kooij, a psychiatrist at VU University Medical Center, Amsterdam, and chair of the European Network Adult ADHD.
Since this study remains ongoing, Dr. Kooij focused instead on the evidence suggesting that ADHD and sleep problems have a shared etiology.
Multiple studies have shown that roughly 75% of children and adults with ADHD have sleep-onset insomnia. It takes them longer to fall asleep, and they have a shorter than normal sleep duration because they have to get up in the morning for school or work. Dr. Kooij and her colleagues have shown that in adult ADHD patients with delayed sleep onset syndrome, their evening dim light melatonin onset, change in core body temperature, and other physiologic harbingers of sleep are delayed by an average of 1.5 hours ().
“My ADHD patients sleep a mean of 5-6 hours per night on a chronic basis, versus 7-8 hours in normal individuals. It leads to daytime sleepiness and dysfunction due to inattentiveness and social problems,” the psychiatrist said.
Other investigators have demonstrated that the prevalence of ADHD varies across the United States and that geographic differences in solar intensity explain 34%-57% of this variance in ADHD rates. The investigators postulated that the ADHD-preventive effect of high solar irradiation might be tied to improvement in circadian clock disturbances (Biol Psychiatry. 2013 Oct 15;74:585-90).
In a study of 2,090 adult participants in, Dr. Kooij and her colleagues showed that ADHD, depression, anxiety, and circadian rhythm sleep problems are fellow travelers.
The prevalence of sleep duration of fewer than 6 hours per night was 15% in subjects with high ADHD symptoms and a lifetime history of an anxiety and/or depression diagnosis, 5% in those with lifetime anxiety/depression but no ADHD, and 4% in healthy controls. Delayed sleep phase syndrome was present in 16% of individuals with ADHD and a history of depression and/or anxiety, 8% in those with a lifetime history of anxiety/depression without ADHD, and 5% of healthy controls. The take-home message: Circadian rhythm sleep disorders in patients with ADHD are not necessarily attributable to comorbid anxiety and/or depression ().
Seasonal affective disorder is commonly comorbid with ADHD. In another analysis from The Netherlands Study of Depression and Anxiety, Dr. Kooij and her colleagues determined that the prevalence of probable seasonal affective disorder using thewas 9.9% in participants with clinically significant ADHD symptoms, compared with 3.3% in the non-ADHD subjects. Self-reported delayed sleep onset was extremely common in participants with ADHD as well as in those with probable seasonal affective disorder ( ).
Patients with ADHD have an increased prevalence of obesity. Their chronic short sleep pushes them toward an unstable eating pattern in which they skip breakfast, then engage in binge eating later in the day. The hope is that treating the circadian rhythm disruption associated with ADHD will prevent obesity in this population ().
“If you mess up sleep, you mess up the body: bowel movements, blood pressure, body temperature, the leptin/ghrelin ratio, reaction time, coordination. That’s why I call my patients chronically jet-lagged,” Dr. Kooij said.
She reported having no financial conflicts regarding her presentation.