Inadequate sleep associated with neurocognitive difficulties in children with insomnia

Results from the Adolescent Brain Cognitive Development (ABCD) study showed an association between inadequate sleep in children aged 9 to 10 and difficulties in neurocognitive development.¹ Findings highlighted the major impact that poor sleep habits have on the development of their neurocognitive skills and focused on promoting interventions for children that improve sleep habits and therefore developmental outcomes.²

In the study, participants were classified as either insufficient sleepers (n=4181) or adequate sleepers (n=4142). Consistent with previous findings, the data showed that insufficient sleep had widespread effects on basic behavioral measures. Specifically, 32 of the 42 baseline assessments used showed a significant difference between the adequate and insufficient sleep groups after adjusting the propensity score. Similar patterns and effect sizes were observed at 2-year follow-up. Using Cohen’s ds of the difference between the adequate and insufficient sleep groups at the 2-year follow-up, the researchers found that these effects were significantly correlated (right = 0.85; 95% CI, 0.73-0.92; P <.001), suggesting that insufficient sleep has stable effects on adolescents' behavioral problems, neurocognition, and mental health.

Co-author Fan Nils Yang, PhD, Postdoctoral Fellow, University of Maryland was interviewed by NeurologyLive^® to discuss more details about the study, including his thoughts on what its findings mean for future patients with insomnia and recommendations for future studies.

NeurologyLive^®: Can you explain the study you conducted in more detail?

Fan Nils Yang, PhD: In this study, we provide strong evidence on the effects of insufficient sleep on the brain and behavior of early adolescents over a two-year period. Specifically, using a population-based sample from the ABCD study (over 11,000 9-10 year olds) and advanced statistical methods, we found that sleeping less than 9 hours per day is associated with impaired cognitive and affective functioning in both Baseline and two-year follow-up. We also identified two neural mechanisms underlying these effects of insufficient sleep. Our results could provide empirical and theoretical foundations for early sleep intervention programs to improve long-term developmental outcomes in adolescence.

What could your study mean for the future of patients with insomnia?

Adolescence is a crucial period for brain and cognitive development. For adolescents with insomnia, our study showed the consequences of lack of sleep. For example, if someone consistently sleeps less than the recommended amount due to insomnia, the brain regions responsible for emotional regulation and memory will malfunction, leading to affective and cognitive dysfunction. Given that these consequences could be long-lasting, according to our study, early intervention for insomnia is needed in adolescents. In addition, previous studies3 have shown that sleep problems and mental health problems can exacerbate each other. Treating the underlying cause is just as important as maintaining good sleep hygiene.

Did you find something surprising in your results?

There are two results that surprised us. First, I did not expect the effects of insufficient sleep on the brain at baseline, and behavior is stable at the two-year follow-up. In other words, if a child was not getting enough sleep by the age of 10, their brain and behavior would still be suffering from the effects of the lack of sleep by the age of 12. Second, previous literature suggests that liquid intelligence in children is more prone to sleep loss than crystallized intelligence. In contrast, our study shows the opposite. This discrepancy could be because we have a large sample size and carefully controlled key sleep duration covariates that may not have been possible in previous research.

What should be done in future studies in this research area?

We have shown that sleep duration has long-term effects on the brain and behavior. Future studies could test whether or not these effects are reversible, and if they are, what is the best intervention for the effects caused by insufficient sleep.

REFERENCES
1. Yang FN, Xie W, Wang Z. Effects of sleep duration on neurocognitive development in early adolescents in the US: a propensity score-matched longitudinal observational study. Lancet Child Adolesc Health. 2022;6(10):705-712. doi:10.1016/S2352-4642(22)00188-2
2. University of Maryland School of Medicine. Children who lack sleep can experience adverse effects on brain and cognitive development that persist over time: research has found that sleeping less than nine hours a night is associated with cognitive difficulties, mental health problems and less gray matter in certain brain regions are connected. ScienceDaily. July 30, 2022. Accessed October 19, 2022. www.sciencedaily.com/releases/2022/07/220730125455.htm
3. Yang FN, Liu TT, Wang Z. Functional connectome mediates the link between sleep disorders and mental health in preadolescence: A longitudinal study of mediation. Hum Brain Map. 2022;43(6):2041-2050. doi:10.1002/hbm.25772