Dose-Dependent Link Between Sleep and Unsafe Teen Behavior

Pauline Anderson

October 16, 2018

Results of a large study suggest a dose-dependent relationship between getting less than 8 hours of sleep and increased risky behaviors among teens, including risk-taking while driving, use of alcohol and drugs, risky sexual activity, aggressive behavior, feelings of hopelessness, and self-harm.

Dr Matthew Weaver

"Insufficient sleep may be a driver of several significant public health concerns among youth, and this would include mental health and substance abuse," author Matthew D. Weaver, PhD, an epidemiologist, sleep researcher, and instructor in medicine at Harvard Medical School, Boston Massachusetts, told Medscape Medical News.

"These behaviors are common precursors to accidents and suicides, which are the leading causes of death for this age group," he said.

The study was published online October 1 as a research letter in JAMA Pediatrics.

Researchers have examined the impact of sleep habits in various populations, the investigators note. Studies of college students found that sleep duration and regularity are important predictors of academic performance and that lack of sleep affects mood, metabolism, and general health.

"We were interested in exploring the impact of similar exposures in a younger group of people and looking at a more diverse set of potential outcomes," said Weaver. "We felt that the impact of sleep deficiency among teens had been understudied."

For this new study, researchers used data from the Youth Risk Behavior Survey between February 2007 and May 2015. This survey is administered biannually to a nationally representative sample of students at public and private high schools.

The investigators categorized sleep duration on an "average" school night as 8 hours or more, 7 hours, 6 hours, or less than 6 hours.

They examined risk-taking behaviors and controlled for age, sex, race/ethnicity, and year of survey. Student participation in the survey was anonymous and voluntary.

The study included 67,615 surveys. About half of participants were female, and most (58.4%) identified as white.

Only 30.4% of students reported getting 8 or more hours of sleep on an average school night. According to the American Academy of Sleep Medicine (AASM), most students in this age group need 8 to 10 hours of sleep a night.

Less and Less Sleep

Sleep deficiency increased over time, from 68.9% in 2007 to 71.9% in 2015, results showed.

Several factors likely contribute to this, said Weaver. For example, there's a growing expectation for high school students to participate in after-school activities, which could affect time for other activities, including sleep.

It is well known that having laptops, smartphones, and other devices in the bedroom contributes to distractions that interfere with sleep, he said.

Prescriptions for stimulants to treat attention-deficit/hyperactivity disorder (ADHD) could also be affecting sleep among teens.

"Symptoms of ADHD are similar to, and overlap with, those of sleep deficiency," said Weaver. "If a child is sleep deficient and is prescribed ADHD medications, the stimulants will make it that much more difficult to get the sleep they need."

The analysis showed that compared with getting 8 or more hours of sleep, getting less increased the odds of risk-taking while driving a vehicle. At 7 hours vs 8, the odds ratio (OR) was 1.19 (95% confidence interval [CI], 1.12 - 1.26); for 6 hours, the OR was 1.37 (95% CI, 1.29 - 1.46); and for less than 6 hours, the OR was 1.75 (95% CI, 1.61 - 1.91).

The study showed a similar dose-dependent relationship between shorter sleep duration, use of alcohol and other drugs, risky sexual activity, and aggressive behaviors.

The strongest associations were with mood (feeling sad or hopeless) and self-harm.

Those who slept less than 6 hours were more than three times as likely as those who slept at least 8 hours to report considering suicide (OR, 3.12; 95% CI, 2.85 - 3.41) or making a plan to attempt suicide (OR, 3.17; 95% CI, 2.87 - 3.51).

They were also more than four times as likely to report an attempted suicide that resulted in treatment (OR, 4.24; 95% CI, 3.53 - 5.10).

Consistent Results

The researchers were "a little surprised" by the strength of the associations, particularly with regard to the mood and suicidality outcomes, said Weaver. They were also somewhat taken aback that the results were "so consistent" across the different behaviors, he added.

"Sleep was significantly associated with every behavior that we studied," he said.

In addition to using a much larger data set and a more diverse set of potential outcomes than previous research, this new study assessed the impact of sleep deprivation over a longer period, he noted.

Weaver believes more research is needed to determine the specific relationships driving the associations between sleep deprivation and unsafe behaviors.

"But meanwhile, our findings suggest that we should continue to support efforts to promote healthy sleep habits and decrease barriers to sufficient sleep in this population," he said.

Clinicians should discuss sleep habits with young patients, along with diet and exercise, said Weaver.

"Sleep impacts all aspects of your life, from academic and athletic performance to mood," he said.

Commenting on the study for Medscape Medical News, Nathaniel F. Watson, MD, professor of neurology, University of Washington (UW), director, UW Medicine Sleep Clinic, and past president of the AASM, said it's "further evidence of the importance of sleep to adolescent health and well-being and academic performance."

Clinicians and others need to "wake up and pay attention" to this issue and be part of a "boots on the ground" lobby for middle school and high school schedules "that align with adolescent circadian physiology," said Watson.

Although school start times vary from school to school and from district to district, many classes start well before 8:30 AM. The AASM recommends starting at this time or even later.

"Part of the problem is that there is no real state-wide legislation or federal legislation to address this issue," said Watson.

"We live in a day and age where sleep is considered noncompulsory," he said. "People believe that somehow they can hack their sleep, and that just isn't the case; there's no substitute for sleep. Sleep is every bit as important to your health and well-being as diet and exercise, and as a society, we need to start evaluating it in that manner."

Watson agreed that physicians should "certainly" be screening young patients for sleep disorders and discussing the importance of sleep with them.

Healthy sleep hygiene "doesn't cost a dime," he said. Part of it involves going to bed when feeling drowsy and waking up spontaneously, without relying on an alarm clock.

When patients start getting enough sleep, they have more energy and improved mood and interpersonal relationships, in addition to better cardiovascular and metabolic health, he concluded.

Dr Weaver and Dr Watson have disclosed no relevant financial relationships.

JAMA Pediatrics. Published online October 1, 2018. Abstract

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