Children with ADHD often struggle with poor sleep, but are highly likely to sleep no worse than others by adulthood if their ADHD resolves, new research from Goldsmiths, University of London and King’s College London suggests.
In a study of 2,232 twins from England and Wales, researchers found that among individuals whose ADHD resolved by young adulthood, sleep quality was no worse than those who had never had ADHD.
A total of 247 participants met criteria for attention deficit hyperactivity disorder in childhood, but a large proportion (78%) of these individuals no longer had the disorder in adulthood. Among these individuals, sleep quality was no different than those who never had ADHD in childhood.
However, the researchers found that among the smaller number of participants with ADHD as children who still had the disorder in young adulthood, sleep quality was poorer at 18 years old compared to those never diagnosed with ADHD.
The association between ADHD and poor sleep in adulthood remained when taking into account a variety of mental health issues also associated with poor sleep quality.
“We think that this provides a positive message for families struggling to cope with sleep problems in children with ADHD: this disorder may well resolve over time and if it does, it is likely that associated poor sleep will also be a thing of the past too.”
ADHD and poor sleep quality may be inherited together and share environmental causes too
But why does ADHD so often come hand in hand with poor sleep in young adulthood? Previous research suggests that medication for ADHD could lead to poor sleep quality, while other studies have focused on common neurobiological pathways influencing both ADHD and sleep quality or on different environmental factors.
The twin design of this study allowed Professor Gregory and her colleagues to better understand the genetic and environmental influences on the association between ADHD and sleep quality. The research team wanted to understand whether ADHD and sleep problems occurred together because of underlying shared genetic causes or because of shared non-genetic, environmental causes.
Focusing on adulthood, the genetic contribution to ADHD and sleep problems was similar in size. Additionally, looking at the overlap of ADHD and sleep problems, the team found that about half of the association between these two factors was explained by common genetic influences (55%) and another half (45%) by environmental influences.
Based on this work, it appears that ADHD and sleep problems have common origins, which are influenced both by genes and the environment. These findings point to possibilities for further research into the links between ADHD and sleep.
Future research needs to specify the genes involved in both sleep and ADHD, as well as to understand the environmental factors which could contribute to their co-occurrence. Could the onslaught of technological advances – with mobile phones left on the pillow case and checked last thing at night - be important?
ADHD and Sleep Quality: Longitudinal Analyses From Childhood to Early Adulthood in a Twin Cohort by Alice Gregory (Goldsmiths), Jessica Agnew-Blais, Timothy Matthews, Terrie E. Moffitt and Louise Arseneault (King’s College London) was published in the Journal of Clinical Child and Adolescent Psychology on Wednesday 3 August.