Smartphones and sleep deprivation: a toxic combination for teens

Recently I posted a comment on Facebook, then obsessed for several hours when no one in my inner circle of friends had liked it. I am 40 years old, with a fully developed prefrontal cortex that is (usually) capable of regulating my emotional responses and decisions. I can only imagine what the adolescent brain does in such a situation.

Smartphone use is doing far more than keeping teens awake.

Smartphone use is doing far more than keeping teens awake.

Teenagers’ prefrontal cortexes are still growing. As that part of the brain matures, adolescents “can reason better, develop more control over impulses and make judgments better.” (source) An immature prefrontal cortex cannot perform the same executive function. That’s one reason teens tend to be less responsible and more prone to taking risks than adults.

It’s also a reason teens are more vulnerable to potentially upsetting stimuli such as comments on social media and online bullying. Researcher Jean Twenge reports that a rise in smartphone use (synonymous with social media use for most teens) has corresponded with a dramatic rise in teen depression and suicide.

Compounding this problem is another effect of heavy smartphone use: sleep deprivation. Teens already don’t get enough sleep, in part because of changes in adolescent circadian rhythms combined with early start times at school. A study of 27,939 adolescents in Fairfax County, Virginia found that high school students slept an average of 6.5 hours each night, far short of the 9 hours sleep experts and pediatricians recommend for this age group. Sleep deprivation did more than cause students to nod off in class; the researchers observed that “just 1 hour less of weekday sleep was associated with significantly greater odds of feeling hopeless, seriously considering suicide, suicide attempts, and substance use.”

Smartphones and social media keep teens up past their ideal bedtimes, and the sleep they lose may make them more likely to continue to compulsively check social media. It’s a vicious cycle with serious consequences for their mental health.

We protect teens from themselves (and others from their actions) as a matter of course; in most states they can’t drive until they’re 16, and they can’t buy tobacco until age 18 or alcohol until age 21. As a society we accept that adolescents aren’t ready to make decisions that will affect them long-term. Most parents have in-house rules about drinking, smoking, and access to the family car.

Little data exist on how many parents restrict their teens’ usage of smartphones, perhaps because the technology is so new; most of us didn’t grow up with it, and we’re still coming to terms with its effects. But given the link between heavy smartphone use and declines in adolescent mental health, it would be wise to take these devices more seriously, and perhaps take them out of teens’ hands more often.

Learn more:

  • TED talk “Why school should start later for teens” by sleep researcher Wendy Troxel
  • NYT article “The Science of Adolescent Sleep” by