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Sleep is a huge problem for adults with ADHD. Recent studies estimate that up to 83% of patients suffer some type of sleep disturbance. But despite this close correlation, there’s a surprising lack of scientific research to explain exactly why ADHD patients are such bad sleepers.

One of the reasons for this gap in our knowledge is because the sleep/ADHD relationship raises a chicken and egg question: is ADHD (and its associated medication) the cause of sleep problems, or is it the other way round, i.e. do existing sleep problems cause ADHD?

Studying the rhythms

Most sleep/ADHD studies to date have focused on children with attention deficit disorders, so relatively little is known about the sleeping patterns of adults with ADHD. But new research published in 2012 is beginning to shed some light on this area, in particular about the circadian rhythms of adults with ADHD.

Circadian rhythms refer to the built in 24 hour internal clock which governs our sleep wake cycle. In normal healthy individuals, this clock is linked to the light/darkness cues of day and night. As darkness approaches, the hormone melatonin is secreted by the pineal gland inducing drowsiness. Similarly, the light of dawn signals other physiological responses to facilitate wakefulness.

To monitor these changes, the scientists fitted the participants with actigraphs to measure their movements during sleep, and took saliva samples at regular intervals to measure melatonin levels. They also took readings of two ‘clock’ genes, and another hormone, cortisol which also varies with circadian rhythm.

The measurements clearly demonstrated a wide range of sleep disturbances in the ADHD patients. Compared to the control group, night time activity levels were higher, sleep duration was shorter and over half of the adults with ADHD took an hour or longer to fall asleep,

But perhaps more intriguing were the discoveries regarding the circadian rhythms of the ADHD group. They showed a marked preference towards ‘eveningness’ or ‘owl’ behaviour, i.e. they slept and woke later. This tallied with their cortisol levels, which peaked 3 hours later than the control group.

The ADHD group also expressed a much weaker melatonin cycle, whilst their clock genes, compared to a steady pattern for the non-ADHD group, showed a complete breakdown i.e. no rhythm at all. The study concluded that: “adult ADHD is accompanied by significant changes in the circadian system, which in turn may lead to decreased sleep duration and quality in the condition

What are the implications?

Whilst this was a small-scale study, the findings raise some interesting questions. Do faulty circadian rhythms lead to ADHD? Can ADHD symptoms be treated in the same way as circadian rhythm disorders i.e. with melatonin or light therapy? Is there a link between the altered cortisol response (which is also a stress hormone) and the mood and anxiety disorders common in ADHD patients? If nothing else, the results of the study suggest an interesting direction for new research.

What practical steps can be taken?

The good news is that these days you don’t have to go to a sleep laboratory to find out what your sleep patterns look like. You can examine your own circadian rhythms just by downloading an app onto your smartphone. More advanced systems such as the Zeo Sleep Manager can track your sleep patterns and provide you with detailed graphs showing you exactly how much REM and deep sleep you’re getting. Alternatively, just use a pen and paper and start to make a log of your sleep habits, including sleep duration, wake time and when you feel drowsy during the day.

Gathering the data is just the first step. Once you have more information about your personal sleep patterns, consider talking with a health professional about how you can make a positive change to your life by tackling your sleep problems.

This is a guest post by Jeff Mann,  owner of Sleep Junkies, a website dedicated to bringing you the latest research, news and tips about sleep to make you healthier, happier and smarter.


Image courtesy of Ambro at