Researchers at the Douglas Mental Health University Institute and McGill University in Montreal have spent years examining the sleep of children diagnosed with ADHD. In a study published in 2007 in the journal Sleep, Dr. Ruet Gruber and colleagues looked at the performance of 37 six to twelve year olds with ADHD on a test of a measure of attention. The quality of participants’ sleep was assessed in their home using miniature actigraphs, wristwatch-like devices that measure movement. An analysis of movement allowed the researchers to determine whether the kids were asleep or awake; if they moved as much or more than they did during the day, they were rated as being awake. Otherwise, they were classified as being asleep.
The researchers were interested in the children’s sleep efficiency – the percentage of time in bed that was spent sleeping – and they divided the participants into a poor sleep group and a good sleep group based on this score. They found no other differences between the groups (e.g., on anxiety, depression, IQ, or other measures); poor sleepers, whether they were taking medication or not, spent more time awake than good sleepers, woke up more often during the night, and moved more often. No changes in sleep occurred when children were taking a placebo compared to their regular stimulant medication. After a few days of monitoring, the children were asked to complete a continuous performance task (CPT); this is a computer program that requires the participant not to press a key when they see a particular letter on the screen, but to press the key when they see any other letter. Reaction time and errors are recorded. They also examined changes in behaviour related to taking stimulant medication or a placebo.
In the poor sleep group, children who were on medication performed better on the CPT test than their peers who took a placebo. The behavioural symptoms of the participants who took medication were “marginally better” for kids in the poor sleep group who took the stimulant. For the good sleep group, ADHD medication was related to NO DIFFERENCE in performance on the CPT or in ADHD symptoms! Considering that some studies report that between 25 and 50% of children with ADHD also have sleep problems, this is a major finding. The authors theorized that stimulant medications increase physiological arousal, which is low for kids with the disorder, to a moderate level that allows them to focus more easily; sleep also allows children to “recharge their batteries,” possibly bringing the physiological arousal levels of kids with ADHD closer to those without the disorder.
What does this mean for kids? If these findings are accurate, it suggests that sleep differences may be related to ADHD symptoms and addressing sleep problems might have a positive impact on daytime performance. Obviously, since this was a small study in which most of the participants were boys, further work is needed to replicate the findings. However, it may be a particularly promising result for parents who are reluctant to medicate their children, since psychological treatments have been found to be as effective as medication for addressing sleep problems!
You can read more about the sleep study here. The entire article is available for download as a .pdf.
If you browse through the Family Anatomy site, you might notice that several of my recent posts have been about the positive effects of sleep – maybe I need a nap!
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