Study: Vitamin D Insufficiency Worsens Sleep Problems in Children with ADHD

April 29, 2025Vitamin 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.1Children 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, 5This 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.