Risky Behaviors Among Sleep-Deprived Teens

Welcome to “this week in parenting research”, a biweekly (mostly) column where I take a look at new research that may be of interest to parents or anyone who works with kids.

This week, I’m focusing on an interesting report from the CDC. For those of you who have never read it, the Center for Disease Control’s Morbidity and Mortality Weekly Report is pretty interesting. Every week they put up a variety of reports, alerts, surveillance summaries, and other information of general interest within the public health realm. It’s mostly US focused, but also has updates on public health crises from other countries.  I try to check it out at least once a week (okay, that’s partially because I’m taking epidemiology this semester), but it’s worth a look at least occasionally regardless.

This week there was an interesting report on sleep and injury risk among high school students that looked worth paying attention to. It’s been known for a while that kids who don’t sleep much are at higher risk for unintentional injuries, mostly due to car crashes. It’s known that being tired can make you a worse driver, but researchers wondered if there were other effects as well. This analysis wanted to see if there were less obvious connections, like an increase in risk taking behavior.

So where’d they get their data?

In odd numbered years, the CDC conducts a survey called the Youth Risk Behavior Survey.  This study looked at the 2007, 2009, 2011 and 2013 survey.  The surveys are all self-reported, and they compared reported hours of sleep on an average school night with various behaviors that could put you at risk for a serious injury: not wearing a seatbelt while driving or bicycle helmet while biking, drunk driving or driving with a drunk driver, or texting while driving. Overall the survey covered over 50,000 high school students from across the USA.

All sleep averages are for school nights only, since unsurprisingly most teens vary their sleep on the weekend. For reference, the National Sleep Foundation recommends teens get 8-10 hours of sleep per night….slightly more than adults.

So how much are kids sleeping?

These results were a little sad. Almost 70% of kids weren’t getting enough sleep…less than 7 hours a night. A little over 15% reported they actually got 5 hours or less per night. This was worse for kids the older they got (freshmen slept more than seniors) and a little worse for girls than boys. Now people typically under-report their average sleep (everyone remembers their all nighter!), but that’s still a lot of potentially sleep deprived kids.  Interestingly, 1.5% of kids actually reported getting MORE than 10 hours of sleep on school nights.

How did hours of sleep correlate with risky behaviors?

The amount of sleep a kid got was associated with risky behavior on BOTH ends of the sleep spectrum. Kids who slept less than 7 hours a night and kids who slept more than 10 hours a night during the week were more likely to engage in all 5 risky behaviors they looked at.  For low sleepers, the risk was pretty linear: those who reported sleeping less than 4 hours per night were at a higher risk than those reporting 6 or 7 hours a night. The association was particularly strong for driving drunk and failure to wear a seat belt.

What did they conclude?

So right up front, they know correlation isn’t necessarily causation. It’s possible that a lack of sleep leads to worse decision making, that kids who take risks end up sleeping less, or that something else (like depression) causes sleep problems AND increases risk-taking behavior. A link between depression and teenage risk taking behavior has been previously found, and it would explain why teens who slept a lot showed an increase as well.

For any particular teen, any of the above options could be true.

Regardless, the relationship between sleep and unintentional injury risk is clear and appears to be true on several dimensions.

So what do I think?

While parents often don’t know how many risks their teens are taking when they are not around, it’s interesting to think that sleep patterns may give a general impression of how your kid is doing. I was alarmed to read that over a quarter of teens reported they had gotten in a car with a driver who had been drinking in the last 30 days, and was interested that the CDC has a whole section of their website dedicated to helping parents help their kids to be better drivers.

I know at least when I was a teenager I never realized how much a lack of sleep affected me, and I think emphasizing to your kids how important it is could be helpful.  There’s also some intriguing suggestions that starting the school day later could help with this issue….but that’s a paper for another day.

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