September 11, 2017
2 min read

Expert theorizes ADHD may be a sleep problem

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ADHD may primarily be a problem associated with abnormal circadian sleep, according to an expert at the European College of Neuropsychopharmacology Congress.

“There is extensive research showing that people with ADHD also tend to exhibit sleep problems,” Sandra Kooij, MD, PhD, of VU University Medical Centre, Amsterdam, and founder of the European Network Adult ADHD, said in a press release. “What we are doing here is taking this association to the next logical step: Pulling all the work together leads us to say that, based on existing evidence, it looks very much like ADHD and circadian problems are intertwined in the majority of patients. If you review the evidence, it looks more and more like ADHD and sleeplessness are two sides of the same physiological and mental coin.”

According to Kooij, 75% of individuals with ADHD exhibit a 1.5-hour delay in the physiological sleep phase as well as delayed core body temperature changes associated with sleep.

Several sleep-related disorders, such as restless leg syndrome, sleep apnea and circadian rhythm disturbance, are associated with ADHD.

Individuals with ADHD often have greater alertness in the evening, opposing typical behavior in the general population, according to Kooij.

“We are working to confirm this physical-mental relationship by finding biomarkers, such as vitamin D levels, blood glucose, cortisol levels, 24-hour blood pressure, heart rate variability and so on,” Kooij said in the release. “If the connection is confirmed, it raises the intriguing question: Does ADHD cause sleeplessness or does sleeplessness cause ADHD? If the latter, then we may be able to treat some ADHD by non-pharmacological methods, such as changing light or sleep patterns, and prevent the negative impact of chronic sleep loss on health.”

Many individuals with ADHD benefit from taking melatonin in the evening or receiving bright light therapy in the morning, which can reset the circadian rhythm, according to Kooij.

“We don’t say that all ADHD problems are associated with these circadian patterns, but it looks increasingly likely that this is an important element,” she said.

Recent findings indicated approximately 70% of individuals with ADHD exhibited light oversensitivity and wore sunglasses during the day, which Kooij reported could reinforce issues associated with a “circadian shift.”

According to Andreas Reif, MD, of University Hospital, Frankfurt, a disturbance of the circadian system may indeed be a core mechanism in ADHD, which could also link ADHD to other mental illnesses such as depression or bipolar disorder.


“But also beyond these pathophysiological considerations, sleep problems and abnormalities of circadian rhythms are a huge problem for many patients, heavily impacting on their social life,” Reif said in the release. “More research into the interconnections between ADHD and the ‘inner clock’ is thus very relevant to improve patients’ lives and to shed light on the disease mechanism of ADHD.” – by Amanda Oldt


Kooij S. Circadian rhythm and sleep in ADHD — Cause or life style factor? Presented at: European College of Neuropsychopharmacology Congress; Sept. 2-5, 2017; Paris.

Disclosures: Kooij reports she has received funding from the Dutch Expertise Center Adult ADHD, at PsyQ in The Hague, Netherlands. was unable to obtain relevant financial disclosures for Reif at the time of publication.