The scientific debate over teens, screens and mental health

More teens and young adults — particularly girls and young women — are reporting being depressed and anxious, compared with comparable numbers from the mid-2000s. Suicides are up too in that time period, most noticeably among girls ages 10 to 14.

These trends are the basis of a scientific controversy.

One hypothesis that has gotten a lot of traction is that with nearly every teen using a smartphone these days, digital media must take some of the blame for worsening mental health.

But some researchers argue that this theory isn't well supported by existing evidence and that it repeats a "moral panic" argument made many times in the past about video games, rap lyrics, television and even radio, back in its early days.

To understand both sides of the debate, I talked in detail to three researchers: one who argues that teens' use of tech is a big problem, one who thinks the danger is exaggerated and an expert in research methodology who suggests the connection may not be so simple.

Very concerned about smartphones

Jean Twenge, a professor of psychology at San Diego State University, may be the researcher most associated with the idea that smartphones are dangerous to teens. She's the author of the book iGen, whose 27-word subtitle states her thesis: Why Today's Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood — and What That Means for the Rest of Us.

"At first, when I saw these trends in loneliness and unhappiness and depression starting to spike around 2011 or 2012, I really had no idea what could possibly be causing that. It was a real mystery," she tells NPR. Then, she says, she took note of Pew research that showed 2012 was the first year that most cell phone owners had switched to smartphones.

Not only do these two trend lines seem to coincide in time, but Twenge also notes that young people who report spending the most time on smartphones — five to seven hours a day — are twice as likely to report being depressed as those who use their phones for one to two hours a day.

Twenge isn't claiming to have proved that smartphones cause depression. The data sets she works with — essentially large surveys — don't allow for that.

"It is impossible to do a random controlled trial on generations because you can't randomly assign people to be born at different times. So we cannot prove causation given that limitation," she explains. "So we have to go on the data that we have — which is obviously not going to be a true experiment — but it adds up to a lot of evidence pointing toward technology possibly playing a role in this increase in mental health issues."

Evidence — with caveats

Given that all teens use media, I asked Twenge, why would the worsening trend in mental health be more pronounced in girls than in boys?

She responded with one possible explanation: Social media, which girls tend to spend more time on, may be the culprit.

"Social media invites comparison," Twenge says. "It's not in real time. It invites anxiety over the likes and responses that you're going to get."

Given that adults use media even more than teenagers, why does this trend crop up in teens? Twenge says it's because their brains are still vulnerable and developing. Plus, they haven't had as much time to make social connections in real life as older people have, so they are even more dependent on their phones for social validation.

Twenge even thinks that the availability of smartphones could help explain the rise in suicide rates among the youngest girls. "They have more access to information online — potentially harmful information about how to harm yourself."

My final question for Twenge: She, personally, made a very similar argument about young people before smartphones existed. She previously published a book, Generation Me, that looked at similar data sets and labeled the millennial generation as "miserable," "narcissistic" and "anxious." That book came out in 2006; the iPhone was introduced in 2007. Is she putting old wine in new bottles?

Twenge says that comparing then with now, mental health trends are even more negative for what she calls iGen and, in retrospect, "more of a mixed bag" for millennials.

Not worth the time

Parents are concerned. Detox programs have sprung up to treat teen tech addiction. But some researchers are skeptical of the hypothesis that smartphones cause problems.

One team has published three papers that analyzed the same data Twenge is looking at — over 350,000 participants in three nationwide surveys in the U.S. and the United Kingdom.

Amy Orben, the lead author of each paper and a psychologist at Oxford University, says the team found that the actual negative relationship between teens' mental health and technology use is tiny.

"A teenagers' technology use can only explain less than 1% of variation in well-being," Orben says. "It's so small that it's surpassed by whether a teenager wears glasses to school," or rides a bicycle, or eats potatoes — all comparisons made by Orben and her Oxford co-author Andrew K. Przybylski.

How can this be? Well, smartphone use is almost ubiquitous among teenagers today, while only a small minority report mental health problems. So, knowing that a teenager uses a smartphone, even for many hours a day, won't reliably predict that the teenager will become depressed. It tells you far, far less than factors like genetics or the presence of childhood trauma, for example.

Orben has been researching the history of people making dire claims about young people and new forms of media. For example, she says, "In the 1940s, people were already talking about 'radio addiction.' One study found that fully 57% of children ages 6 to 16 were severely 'addicted to radio programs and needed them like an alcoholic does their drink.' "

She thinks the negative trends in mental health could be explained by a wide range of factors: economic anxiety or political upheaval, to name two. And, she adds, there's a chance that young people today may simply be more open in surveys when asked about mental health challenges. "A lot of teenagers are a lot more OK to say they're not OK." Ironically, this openness may in fact be partly due to social media.

Twenge responds that a forthcoming paper she has written, currently under review, will challenge the conclusions of Orben's team. She says that just because the impact of smartphone use appears small, that doesn't mean it's insignificant, especially since, unlike genetics, it may be controllable.

Statistically problematic

As a sort of referee on this debate, I called up Katherine Keyes, an epidemiologist at Columbia University's Mailman School of Public Health. Her focus is on explaining population-wide trends, particularly in adolescent mental health.

She too is a critic of Twenge's work, saying it has a tendency to "skew the data" by zooming in on screen use to the exclusion of other factors in the lives of adolescents.

And, she says, there are lots of numbers that don't necessarily fit Twenge's theory. The uptick in suicides started in 1999. The downturn in teen mental health started in 2005. The iPhone was introduced in 2007 and wasn't accessible to most teenagers for several years.

Not all the news is bad when it comes to teens. High school graduation rates are up, for example. Drug and alcohol use is down, as are car crashes and teen pregnancy.

Adolescent mental health isn't in "free-fall," says Keyes, but seems to have leveled off since a dip in 2012.

We're not seeing the same negative trends in every country, even in those where teens are just as glued to their screens as they are in the United States.

There isn't a linear relationship between screen use and mental health. On most surveys, teens who use their phones up to two hours a day appear healthier than those who don't use them at all. This doesn't count other reasons for technology use, such as homework or listening to music.

In the case of heavy users, Keyes says, smartphone use may be more a symptom than a cause of mental health problems. Or there may be a third variable that is driving both — like a lack of parental support or health issues.

The explanation that Keyes finds most compelling is that there is a "bidirectional" relationship among teens, screens and mental health. In other words, as argued in this paper by Candice Odgers in the journal Nature, teens who are already struggling may be more drawn to screens and more likely to form unhealthy relationships with media, for example by seeking out information on self-harm or encountering cyberbullies. The time they spend online might in turn make them feel worse.

Twenge agrees with the general idea that "social media invites comparisons and anxiety."

What's a parent to do?

Although their conclusions are different, no researcher I've spoken with thinks it's a great idea to let teens scroll through TikTok or play Fortnite all day and night.

Twenge, Orben and Keyes are supportive of similar common-sense rules, like making sure teens don't have their phones in their bedrooms late at night and trying to ensure that their lives are balanced with outdoor exercise, school and face-to-face time with friends and family.

So why should the average parent worry about this scientific controversy? Because, Keyes says, when parents simply demonize phones, "there's less of a communications channel" about what teens are encountering online. A parent's opportunity to mentor or support positive uses of media is replaced by "confrontation on a day-to-day basis." Well-meaning parents, wrongly believing the phone to be as risky as a cigarette or a beer, may actually be making their children's lives harder by fighting with them about it.

Copyright 2019 NPR. To see more, visit https://www.npr.org.