When 12-year-olds struggle with anxiety, parents and doctors often focus on therapy or medication. But a new study suggests there is another factor hiding in plain sight: sleep.
Researchers at UC Davis Health in Sacramento found that sleep quality is the strongest lifestyle habit linked to better grades and fewer social problems in children ages 10 to 13. It even outranked screen time, exercise and diet. The study was published in the journal Psychological Medicine.
"We expected sleep to be important, but we didn't expect it to stand out so clearly above other lifestyle factors, particularly screen time," said Jason Smucny, the study's first author and a computational neuroscientist at UC Davis.
The researchers looked at data from the Adolescent Brain Cognitive Development (ABCD) Study, one of the largest studies of brain development in children in the United States. They examined how four habits—sleep, screen time, physical activity and diet—affected the link between mental health symptoms and everyday functioning in early adolescence, a time when anxiety and depression often first appear.
The numbers were striking. Sleep explained 36.3 percent of the connection between anxiety and school performance, 18.5 percent of the connection between depression and school performance, and 8.3 percent of the connection between psychotic-like disturbances and grades. Screen time came in second, explaining between 5 and 6.3 percent of these associations.
Globally, about one in seven adolescents experiences a mental disorder, and depression and anxiety are the leading causes of illness and disability among young people worldwide, according to the World Health Organization.
"Parents, educators and clinicians understandably focus on symptoms like anxiety and depression," said Tara Niendam, senior author of the study and professor of psychiatry at UC Davis. "But what often matters most to young people and their families is how those symptoms affect everyday life—how they perform in school, connect with friends and navigate daily challenges."
Niendam said the findings suggest sleep may be an important and often overlooked pathway connecting mental health to real-world outcomes. The researchers are quick to note that healthy sleep habits are not a replacement for professional mental health care when needed. But they say the results offer a practical starting point.
"What is encouraging is that sleep is something parents and families can address," Niendam said. "While it won't solve every mental health challenge, healthy sleep routines are a practical way to support a child's emotional well-being and day-to-day functioning."