Study: Vitamin D Insufficiency Worsens Sleep Problems in Children with ADHD
Vitamin D insufficiency increases the risk for poor sleep quality and sleep disordered breathing in children with ADHD, suggests a new study.
April 29, 2025
Vitamin D insufficiency worsens sleep problems in children with ADHD, but it does not directly affect the condition’s symptoms or functional impairments, a recent study published in Frontiers in Psychology found.1
Children with ADHD are more likely to experience vitamin D deficiencies than are children without ADHD, according to previous research.2 However, this study found no causal relationship or direct link between ADHD symptoms and vitamin D insufficiency.
Scientists did find that low vitamin D levels (below 30 ng/mL) can worsen sleep difficulties, impairing sleep quality and worsening sleep disordered breathing, in children with ADHD.
The researchers wrote that sleep difficulties “increased daytime sleepiness, inattention, and oppositional defiant disorder symptoms in children.” Additionally, it was found that sleep disordered breathing can affect a child’s attention, focus, hyperactivity, memory, and executive functioning, essentially exacerbating ADHD symptoms.
Nearly three-quarters of children with ADHD experience a sleep problem or disorder.3 Additionally, up to half of children with ADHD have sleep problems, such as difficulty sleeping, insomnia, night waking, and hypersomnia.4, 5
This is the first study, to the researchers’ knowledge, that examines whether vitamin D insufficiency exacerbates sleep problems and symptoms in children with ADHD. Exploring the impact of vitamin D on sleep in children with ADHD is an important area of study since sleep problems in childhood may last into adolescence and adulthood.
“Poor sleep is a self-fulfilling prophecy,” says Joel Nigg, Ph.D., a clinical psychologist and a professor in the departments of psychiatry and behavioral sciences at Oregon Health & Science University. “Just one night of bad sleep can make a child’s inattention and opposition even worse the next day, in turn making it even more difficult to get ready and settled for sleep the next night. The pattern repeats indefinitely if not arrested.”
The case-control study examined data collected from 260 children with ADHD aged 6 to 14 years, 95 with vitamin D sufficiency and 165 with vitamin D insufficiency, from the Department of Child Health at Dalian Municipal Women and Children’s Medical Center in China.
The researchers noted several study limitations. Sleep information was obtained through subjective reports from the subjects’ parents, and researchers noted differences between these and objective sleep measures. Additionally, the study participants were limited to a group of children from Northeastern China. The sample size of 220 children is also too small to extrapolate the findings to other populations. Furthermore, since all participants had ADHD, there was no control group in this study.
The scientists hope to use the data collected from this study to further explore the relationship between ADHD symptom severity, sleep, and vitamin D levels in future studies with a more representative sample and a control group.
Vitamin D, which is mainly sourced from sunlight, can help with sleep difficulties commonly found in people with ADHD, like sleeping late, waking up throughout the night, or waking up very early. In the past few decades, researchers have found that locations with greater sunlight report lower-than-average ADHD prevalence, suggesting a possible connection between ADHD and vitamin D.6
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1 Zhang, P., Liu, Y., Yan, M. et al. (2025). Vitamin D insufficiency and sleep disturbances in children with ADHD: a case-control study. Frontiers in Psychology. https://doi.org/10.3389/fpsyt.2025.1546692
2Kotsi, E., Kotsi, E., Perrea, D.N. (2019). Vitamin D levels in children and adolescents with attention-deficit hyperactivity disorder (ADHD): a meta-analysis. <em>Attention deficit hyperactivity Disord. </em> https://doi.org/10.1007/s12402-018-0276-7
3 Sung, V., Hiscock, H., Sciberras, E., Efron, D. (2008). Sleep problems in children with attention-deficit/hyperactivity disorder: prevalence and the effect on the child and family. Arch Pediatr Adolesc Med. https://doi.org/10.1001/archpedi.162.4.336
4 Hvolby A. (2015). Associations of sleep disturbance with ADHD: implications for treatment. Atten Defic Hyperact Disord. doi: 10.1007/s12402-014-0151-0
5 Spruyt, K., Gozal, D. (2011). Sleep disturbances in children with attention-deficit/hyperactivity disorder. <em>Expert Rev Neurother.</em>.https://doi.org/10.1586/ern.11.7
6 Miller, M.C., Pan, X. Eugene Arnold, L. et al (2021). Vitamin D levels in children with attention deficit hyperactivity disorder: Association with seasonal and geographical variation, supplementation, inattention severity, and theta:beta ratio. Biological Psychology. https://doi.org/10.1016/j.biopsycho.2021.108099
