Earlier School Start Times May Increase Risk of Adolescent Depression and Anxiety, URMC Study Says

Teenagers with school starting times before 8:30 a.m. may be at particular risk of experiencing depression and anxiety due to compromised sleep quality, according to a recent URMC study.

Involving URMC's Professor of Pediatrics and Chief ofDivision of Pediatric Sleep Medicine, Heidi V. Connolly, MD., the study, recently published in Sleep Health, not only reinforces the theorized link between sleep and adolescent mental health, but is among the first to demonstrate that school start times may have a critical impact on adolescent sleep and daily functioning. The findings provide additional evidence in the national debate over how school start times impact adolescent health.

"Studies consistently show that teens who start school later are more well rested, less likely to be involved in motor vehicle crashes and report better quality of life," said Connolly. "The important part to understand is that by delaying high school start times by for example 30 minutes actually results in teens sleeping MORE than an additional 30 minutes because it brings their sleep times into better alignment with their circadian rhythm."

Connolly is one of many investigators now exploring ways to address what has become a nationwide sleep epidemic among adolescents. About 90% of high-school-aged adolescents get insufficient sleep on school nights, or barely meet the required amount of sleep (8–10 hours) needed for healthy functioning. School start times, among other interventions (ie. limiting electronic use before bedtime), have become a critical point of interest.

The research to date, however, has primarily focused on the academic benefits of delaying school start times for adolescents, rather than examining how earlier start times may disrupt sleep-related processes and affect mental health outcomes.

"The shift to daylight savings time results in a loss of 1 hour of overnight sleep.  It is essentially akin to having an hour worth of jet lag from flying (or driving) across 1 time zone going from West to East," said Connolly. "This transition is associated with adverse health outcomes and leads to daytime fatigue until everyone ‘acclimates’ to the new time. Teenagers are particularly susceptible to this added sleep deprivation because as a group they tend to already be sleep deprived.  In addition, sleep deprivation is associated with higher rates of car crashes and teens are no exception in this situation."

With the help of a grant from the National Sleep Foundation, URMC researchers used an online tool to collect data from 197 students across the country between the ages of 14 and 17. All children and parents completed a baseline survey that included questions about the child’s level of sleep hygiene, family socioeconomic status, their circadian chronotype (roughly, whether you are a “morning person” or “night person”), and their school start times.  They were separated into two groups: those who started school before 8:30 a.m. and those who started after 8:30 a.m. (which is currently the recommended start time for high schoolers by the American Academy of Pediatricians).

Over a period of seven days, the students were instructed to keep a sleep diary, in which they reported specifically on their daily sleep hygiene, levels of sleep quality and duration, and their depressive/anxiety symptoms.

The results showed that good baseline sleep hygiene was directly associated with lower average daily depressive/anxiety symptoms across all students, and the levels were even lower in students with school start times after 8:30. However, students with good baseline sleep hygiene and earlier school start times had higher average daily depressive/anxiety symptoms.

"Consistent sleep for adequate amounts of time on a nightly basis in a cool, quiet and dark sleep environment is important for everyone’s health.  Lack of quality (and appropriate quantity) sleep is associated with all sorts of bad health outcomes," said Connolly. "The most important ones for teens are poorer academic performance, mood dysregulation and increased risk of both car crashes and overall injuries including when playing sports.  In short, we all need to sleep enough to be able to perform at our best."

More studies are definitely needed, but our results help clarify the somewhat mixed findings  with other sleep hygiene-focused interventions, by suggesting that school start times may be a very important contextual factor.

Study co-authors include Ronald Rogge, Ph.D., associate professor of Psychology in the University of Rochester School of Arts & Sciences and Thomas O’Connor, Ph.D., professor in the URMC Department of Psychiatry and director of URMC’s Wynne Center for Family Research.

*For adolescents, good sleep hygiene includes avoiding caffeinated beverages after 6 p.m., turning off phones and electronic devices before bedtime, maintaining a consistent sleep schedule, and getting between 8 and 10 hours of sleep.