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# Sleep patterns
Does sleeplessness cause ADHD? Scientists think it might play a role
Around 75% of children and adults with ADHD also have sleep problems.
ATTENTION HYPERACTIVITY DISORDER (ADHD) may be associated with lack of regular circadian sleep, researchers have claimed.
Circadian rhythm sleep disorders affect how and when a person sleeps, and can lead to them being unable to go to sleep and wake up at ‘normal’ times.
ADHD refers to a group of behavioural symptoms with a neurobiological background, including inattentiveness, hyperactivity and mood swings. Symptoms of ADHD tend to be noticed at an early age and may become more noticeable when a child starts school.
Between 2% and 5% of children and adults suffer from ADHD. Around 75% of people with the condition also have sleep problems, but until now these have been thought to be separate issues.
After compiling the latest research, scientists are proposing a new theory on the subject – that sleeplessness may cause some cases of ADHD.
If this is found to be true, researchers have said some people with ADHD could be treated by non-pharmacological methods, such as changing light or sleep patterns.
This theory is being discussed at the European College of Neuropsychopharmacology (ECNP) conference in Paris this weekend. The ECNP is an independent scientific association dedicated to the science and treatment of brain disorders.
Discussing the research, Professor Sandra Kooij, founder and chair of the European Network Adult ADHD organisation, told the conference: “There is extensive research showing that people with ADHD also tend to exhibit sleep problems.
“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.
We believe this because the day and night rhythm is disturbed, the timing of several physical processes is disturbed, not only of sleep, but also of temperature, movement patterns, timing of meals, and so on.
“If you review the evidence, it looks more and more like ADHD and sleeplessness are two sides of the same physiological and mental coin.”
Changing light or sleep pattern
Kooij said researchers are working to confirm this “physical-mental relationship” by examining markers such as Vitamin D levels, blood glucose levels, cortisol levels, blood pressure and heart rate.
If the connection is confirmed, it raises the intriguing question: does ADHD cause sleeplessness, or does sleeplessness cause ADHD? If it’s 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.
“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,” Kooij stated.
Kooij said the theory is backed up by the following statistics:
- In 75% of ADHD patients, the physiological sleep phase — where people show the physiological signs associated with sleep, such as changes in the level of the sleep hormone melatonin, and changes in sleep-related movement – is delayed by 1.5 hours
- Core body temperature changes associated with sleep are also delayed (reflecting melatonin changes)
- Many sleep-related disorders are associated with ADHD, including restless legs syndrome, sleep apnoea and the circadian rhythm disturbance
- People with ADHD often show greater alertness in the evening, which is the opposite of what is found in the general population
- Many sufferers benefit from taking melatonin in the evening or bright light therapy in the morning, which can help reset the circadian rhythm
- Around 70% of adult ADHD sufferers show an oversensitivity of the eyes to light, leading many to wear sunglasses for long periods during the day – which may reinforce the problems associated with a ‘circadian shift’
Commenting on the research, Professor Andreas Reif, leader of an EU-funded international research project on ADHD (CoCA), said: “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.”
Reif, who was not involved in the research, added: “Sleep problems and abnormalities of circadian rhythms are a huge problem for many patients, heavily impacting on their social life.
“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.”
