The Role of Sleep in Mediating Mental Health Symptoms During the COVID-19 Pandemic in Children with and Without ADHD

<b>Background:</b> The COVID-19 virus is a source of both acute and chronic stress for many people. This stress could uniquely impact children and their mental health. Research has shown that children with neurodevelopmental disorders such as Attention-Deficit/Hyperactivity Disorder (ADHD) are at an increased risk of negative mental health symptoms due to stress, but high-quality sleep may be associated with a protective role against these symptoms. We, therefore, aimed to investigate whether the impacts of COVID-19 and sleep problems were independently linked with children's mental health and to examine whether sleep could mediate the relationship between COVID-19 impact and child mental health. Finally, we sought to compare the degree to which sleep problems could mediate this relationship in children without ADHD and in children with ADHD. <b>Methods:</b> In this cross-sectional study, a total of 304 parents of children were sampled from a larger study investigating the impact of the COVID-19 pandemic on Canadian families and children in the spring of 2021. Parents reported on their children's mental health, sleep, and the impacts of COVID-19 on their child. Of the total sample, 234 children were reported as having an ADHD diagnosis, and 70 children were reported to not have ADHD. <b>Results:</b> We found that both the impact of COVID-19 and sleep problems independently and positively contributed to the mental health symptoms (<i>p</i> < 0.001) experienced by children with ADHD and without ADHD. Children with ADHD were found to have higher scores for COVID-19 child impact, sleep problems, and negative mental health. However, sleep problems had a greater impact on the mental health of children without ADHD compared to ADHD children. Additionally, the results suggest that sleep problems mediated ~20% of the relationship between COVID-19 impact and child mental health in children with ADHD and ~51% of this relationship in children without ADHD. <b>Conclusions:</b> The findings emphasize the significant role of sleep in mediating child mental health symptoms during periods of stress in children without ADHD and in children with ADHD. We highlight the importance of considering sleep quality and supporting healthy sleep in times of stress to improve child mental health symptoms.