For a long time, I’ve been tracking trends in the attitudes and behaviors of teens and young adults. I‘ve relied mainly on a large yearly survey of U.S. teens called Monitoring the Future (MtF). Around 2012 to 2013, the data showed a sudden uptick in teens saying they were experiencing symptoms of depression—feeling hopeless, not enjoying life, believing they couldn’t do anything right. Depression continued to increase over the next few years, making today's teens more depressed than teens just a few years before.

When I dug deeper, I found that the increase in depressive symptoms was only part of the story. Happiness—which had been increasing among teens for 20 years—began to decline. Loneliness spiked sharply, and more students who were entering college (in the national American Freshman survey of 9 million students) said they felt depressed and overwhelmed. Even more concerning, 50 percent more teens in 2015 demonstrated clinically diagnosable depression in a national screening study than just four years before in 2011.  Similar increases showed up in national studies of children and teens hospitalized for suicidal thoughts or self-harm. iGen'ers—today’s teens and young adults—were experiencing a mental health crisis, and no one seemed to know why.

Analyzing MtF and other national data, I was able to rule out a few reasons, including economic troubles, academic pressures, and changes in family structure in this brief window of time.   So, what was it?  Eventually, I learned that, in exactly this same time span, teens were spending less time with their friends in person and more time communicating electronically. Teens were becoming unhappy and depressed at exactly the time that smartphones were becoming ubiquitous—when many teens (and adults) started spending nearly every waking moment looking at their phones. In fact, the Pew Research Center found that the percentage of Americans owning a smartphone rose above 50 percent in late 2012. That was also around the time that social media became almost mandatory for teens. And, both smartphones and social media affected teens directly—a fundamental change in how they spent their time, not just an event in the news or a trend they heard about from their parents.

So I dug deeply into some of the large surveys I already mentioned. In my analyses of MtF and the CDC's Youth Risk Surveillance System data, I found that teens who spent more time on screens were less happy, more depressed, and had more risk factors for suicide. Those links proved to be independent of other factors—such as gender, race, and socioeconomic status.

Of course, correlation doesn’t prove causation. For example, perhaps unhappy people use screen devices more. However, three recent studies seemed to rule out that explanation, at least for social media. Two longitudinal studies found that more social media use led to unhappiness, but that unhappiness did not lead to more social media use. A third study was a true experiment (which can determine causation); it randomly assigned adults to give up Facebook for a week, or not. Those who gave up Facebook ended the week happier, less lonely, and less depressed.

The idea that depression causes social media use also can’t explain why depression increased so suddenly after 2011-12. If the increase in depression occurred first, some other, unknown factor would have had to cause depression to rise so sharply, which would then lead to more smartphone and social media use. It seems much more likely that smartphone and social media use went up, and the increase in depression followed. By far the biggest changes in teens’ day-to-day lives between 2011 and 2015 were the spread of the smartphone and the growth of social media. Nothing else even comes close.

None of this means you should yank the phone out of your teen’s hands. As other studies have documented, light use of smartphones—around an hour a day—is not harmful. In my analyses of data from the Youth Risk Surveillance System survey administered by the CDC, negative effects on mental health appeared only after two or more hours a day of use. Of course, most teens—and many adults—use their smartphones much more than two hours a day (the average is six to eight hours during leisure time), so it makes sense to consider setting limits.

These worrisome trends in mental health among iGen’ers do not mean that good things are not happening in this generation. For example, today’s kids and teens are less likely to drink alcohol or get into physical fights compared to previous generations.  Further, this pattern of smartphone use and mental distress should not be construed as a "criticism" of this generation. As a psychologist, I find that idea antithetical to the basis of my field, which is that mental health issues deserve understanding and compassionate help, not criticism. 

Of course, more research is needed on this important topic.  But right now, the evidence is pretty clear that smartphone and social media use is the most likely reason for a dramatic change in teen happiness and risk of depression in the United States pre-pandemic.  So, as a parent, it’s something I'm addressing with my own children, and an issue I think other parents should consider. Teens and young adults are telling college counselors, survey administrators, and therapists that they are suffering, and we need to listen.


For Further Reading

Shakya, H. B., & Christakis, N. A. (2017). Association of Facebook use with compromised well-being: A longitudinal study. American Journal of Epidemiology, 185, 203-211.

Tromholt, M. (2016). The Facebook experiment: Quitting Facebook leads to higher levels of well-being. Cyberpsychology, Behavior, and Social Networking, 19, 661-666.

Twenge, J. M. (2017). iGen: Why Today’s Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy – and Completely Unprepared for Adulthood. New York: Atria Books.


Jean M. Twenge is a personality and social psychologist who studies well-being, health, and cultural change, especially in teens and emerging adults. 

This blog is a condensed version of an article that appeared in Psychology Today. The original article can be found at https://www.psychologytoday.com/us/blog/our-changing-culture/201708/why-so-many-teens-today-have-become-depressed