Teenagers are spending more and more time on their phones these days. In fact, smartphones have been around long enough now that tweens and teens may not even remember life without them. Unfortunately, growing up on an iPhone may not be very good for mental health.

A new study looked at the rates of depression, suicidal thoughts and suicide risk among teens over a five-year period. Between 2010 and 2015, the CDC had noted a rise in suicide — by about 30% — for people between the ages of 13 and 18, and the new study wanted to understand what might have driven that disturbing increase.

“Parents should try to make non-screen activities as attractive as possible... It is fun to hang out with your friends or play basketball. Just remind kids those things are available, and they're just as fun as trading texts.”

The team, from San Diego State University and Florida State University, examined various trends in those same years, regarding economics, academic pressure and, of course, screen time, and attempted to correlate whether the variables might be related.

The only significant correlation was between cell phone use and suicide. Teens who spent more time looking at their screens were also more likely to be depressed. In contrast, teens who reported spending more time doing sports, working on homework, hanging out with friends in real life, reading print media and going to church tended to be happier.

Another disturbing finding was that the rise in suicidal thoughts and depression was largely driven by teenage girls — their suicide rate rose 65 percent. Teenage girls with severe depression increased by 58 percent. Even suicidality — feeling hopeless, thinking about suicide or attempting it — rose 14 percent. It’s not clear why this is, but it may reflect a fundamental difference in what teenage boys and girls are thinking about when they’re on their phones.

Not surprisingly, kids who used their phones the most had the highest risks. Almost half of those who were on their phones for five or more hours per day had suicidal thoughts. About 28% of teens who were on their phone an hour per day had suicidal thoughts — a little better, but still too high.

Researcher Jean Twenge, author of the book, iGen: Why Today's Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood, and her team did not find links between depression or suicide and other variables, like school pressure and homework or family financial stress. Rising screen time was the variable that had the strongest connection to depression and suicide risk. Although the study was just a correlation, the results reflect an undeniable trend in the last few years — that smartphones have become almost ubiquitous. And this is certainly not the first study to find a link between phones and poorer mental health.

Since smartphones aren’t going anywhere, it’s important to teach your kids about the benefits of limiting their use — and talk with them about the increasing number of mental health issues that seem to be associated with them.

“It's totally unrealistic and probably not even good to think kids will stop using screens,” said co-author, Thomas Joiner, in a statement. “It comes down to moderation. Parents should try to make non-screen activities as attractive as possible because a lot of them are attractive. It is fun to hang out with your friends or play basketball. Just remind kids those things are available, and they're just as fun as trading texts. That's the bottom line.”

The study is published in Clinical Psychological Science.