Washington: Teenagers who start school before 8:30 am are at a higher risk of depression and anxiety, even if they are doing everything else right to get a good night's sleep, a study has found.
The study not only reinforces the theorised 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, published in in the journal Sleep Health, provide additional evidence in the national debate over how school start times impact adolescent health.
"Our study is consistent with a growing body of research demonstrating the close connection between sleep hygiene and adolescent mental health," said Jack Peltz, assistant professor at University of Rochester in the US. "But ours is the first to really look at how school start times affect sleep quality, even when a teen is doing everything else right to get a good night's sleep," said Peltz.
"While there are other variables that need to be explored, our findings show that earlier school start times seem to put more pressure on the sleep process and increase mental health symptoms, while later school start times appear to be a strong protective factor for teens," he said. Peltz is one of many investigators now exploring ways to address what has become a nationwide sleep epidemic among adolescents.
About 90 percent 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, said Peltz. "Looking at school start times as a larger contextual variable that may moderate sleep hygiene, sleep quality and adolescent functioning, fills an important gap in the literature," he said.
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 am and those who started after 8:30 am. 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. "Maintaining a consistent bedtime, getting between 8 and 10 hours of sleep, limiting caffeine, turning off the TV, cell phone and video games before bed - these efforts will all benefit their quality of sleep and mental health," said Peltz. "However, the fact that school start times showed a moderating effect on mental health symptoms, suggests that better sleep hygiene combined with later school start times would yield better outcomes," he said.
