Study: Sleep, Not Screen Time, Is the Strongest Lifestyle Factor for Teen Mental Health

Sleep quality may have a greater impact on adolescents' academic performance and peer relationships than screen time, physical activity, or diet, according to a new study by researchers at the University of California, Davis. The findings were published in the journal Psychological Medicine.

The researchers examined how four lifestyle factors—sleep quality, screen use, physical activity, and diet—were associated with the impact of anxiety, depression, and other mental health problems on the daily lives of children aged 10 to 13 years.

The results showed that sleep quality was the strongest factor linked to better school performance and fewer social difficulties. Screen time ranked second.

The study analyzed data from the Adolescent Brain Cognitive Development (ABCD) Study, a large U.S. research project following children and adolescents over time. The researchers found that healthy lifestyle habits could explain a substantial portion of the relationship between mental health difficulties and problems with learning or social functioning.

Sleep made the largest contribution:

• Sleep quality explained approximately 36% of the association between anxiety and poorer academic performance.

• It accounted for about 18.5% of the link between depressive symptoms and school-related difficulties.

• It explained around 8% of the relationship between psychotic symptoms and academic problems.

Screen time also played a role, but its impact was considerably smaller. It explained approximately 5–6% of the association between anxiety or depression and impaired day-to-day functioning.

By comparison, physical activity and diet were found to have a weaker influence on these outcomes.

According to the study authors, parents, teachers, and healthcare professionals often focus primarily on the symptoms of anxiety and depression. However, for adolescents and their families, it is equally important to address how these conditions affect everyday life, including school performance, friendships, and the ability to manage daily responsibilities.

The researchers emphasized that healthy sleep is not a substitute for professional treatment of mental health disorders. Nevertheless, establishing good sleep habits may be an accessible and effective way to support adolescents' emotional well-being and improve their daily functioning.