Mobile devices have become our alarm clocks and newspapers and, via platforms like Facebook and Instagram, portals to our social lives. With smartphones inhabiting the pockets of roughly three quarters of all Americans and tablets borne by half, a pale blue glow silhouettes modern life.

As screens have become ubiquitous, so has the phenomenon of depressed or suicidal teens, notes Jean Twenge, a psychologist at San Diego State University and the author of iGen: Why Today's Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy—and Completely Unprepared for Adulthood.

In a study published in November in Clinical Psychological Science, Twenge correlates the increasing use of social media, gaming and Internet browsing with rising symptoms of depression and suicidal behaviors in teenagers. Importantly, however, other research has shown that some device use—on social media, in particular—might be positive for people struggling with depression or other serious mental illnesses.

The study led by Twenge collected data on more than half a million American teenagers’ electronic device and online media habits from two national surveys conducted annually since 1991 and involving people ages 13 to 18. When Twenge compared those same teens’ reports of having thoughts of or a plan to commit suicide—or making actual attempts—a third of teens who used devices at least two hours a day acknowledged at least one of these behaviors. That number went up to nearly half among teens who used devices for five or more hours a day. Teenagers who used social media on a daily basis were 13 percent more likely to say they felt depressed than were peers who did not use it every day.

Twenge and other researchers had been seeing dramatically rising rates of depression, especially among teens, over the past five years. “I noticed this very pronounced spike in depressive symptoms around 2012,” she says. According to the data collected annually by the U.S. Centers for Disease Control and Prevention, the teen suicide rate has been climbing steadily since then, too.

One of the biggest things happening in society at exactly the time of the depression spike was a rapid proliferation of smartphones. “[It] was the year the percent of Americans who owned smartphones crossed 50 percent,” Twenge says. By 2015 about 85 percent of young adults had smartphones and were using their devices a lot more, according to a Pew Research Center survey. “There was this turn where it wasn’t just that people had smartphones,” Twenge says. “It became the primary way teens communicated with one another.”

For many teenagers, social media is not simply the primary medium of communication but the epicenter of social life itself. “If you don’t have a Snapchat [account], you’re not connected to anyone in school,” says Aashima, a 16-year-old U.S. high school student. (Her surname is withheld to protect her privacy.)

Not only do students hear about gossip or drama more quickly as pictures and messages blaze through virtual networks; Aashima says social media won’t let ugly rumors fade. “I remember in like fourth grade, we didn’t really have cell phones and [gossip] would just die in school that day,” she says. “But with texts and social media, you can discuss it when you’re home, in the car—anytime.” She adds people will bash each other online over something that happened in school or the way somebody looked one day. “And it just drags on and on and on,” she says.

Social media also opens teens up to the worldwide online community. Aashima says strange men follow her accounts frequently and, as a courtesy, she often returns the favor. “And then they [direct message] me, and then they’re like, ‘What’s up, girl?’ And they just say really gross things. This morning I was dealing with someone like that. Like why do you have to take time out of your day to ask me these kinds of questions?” she says. “I feel like, in their eyes, [I’m] another thing to use—to talk about. It’s just really degrading.” Despite her wariness, Aashima says she still wants to engage with people online. “Even if they’re like the worst person ever,” she says, “you just want everyone to like you and not think bad of you, so you try your best to do that. When that fails, you feel like giving up on yourself, and you just don’t want to live anymore.”

The uptick in teenage depression and suicidality has come almost entirely from young women, based on annual surveys of teenagers and young adults taken from 1991 to 2015 that are part of the University of Michigan’s Monitoring the Future Series, which Twenge also used for her study. Some researchers say they can intuitively see possible reasons for this, although they are unsure of any definite factors. “Girls are very relational, so there’s lots of detailed interactions around their relationships and who is doing what, who is more popular,” says Holly Shakya, a psychologist at the University of California, San Diego, who did not work on Twenge’s study.

Twenge also suggests smartphones’ mere presence may affect physical and mental health. “There’s blue light shining into your eyes and preventing you from feeling tired,” she says. “They’re also psychologically stimulating, and that can lead to you turning your thoughts over and over. In many cases it’s ‘Why didn’t I get likes on that post?’ or ‘Is that other person doing something much more fun than me right now?’” These things can keep people up at night, and sleep-deprived people are more prone to depression, Twenge says.

But much of this is hard to prove, Shakya notes. For example, the new study did not address the question of whether gaming or social media use was more closely tied to depression. It merely correlated self-reported information on electronic device and social media use with suicidality and depression, which does not rule out the possibility that depressed people are likely to spend more time on social media.

Also, Twenge’s study did not delve into exactly what people might have been doing when they were using their devices, says Kelly Aschbrenner, a mental health services researcher at the Geisel School of Medicine at Dartmouth College, who was not involved with the work. The researchers “only ask how often they’re using social media or devices. We don’t know that people are scrolling through social media and viewing content that’s upsetting them or interacting with others in a way that makes them feel bad,” Aschbrenner says.

There are also significant reasons to believe social media can be healthful. “Our studies have shown people with mental health problems can benefit when they connect with others like them [on social media] to share advice [and] ailments and feel that they’re not alone,” Aschbrenner notes. “It’s not like you can go to the park and scream out, ‘Is anyone else feeling anxious today?’ There are really few opportunities for people to find others in life who have the same stigmatized illness.”

Aschbrenner says that although it is important to consider the risks of new technologies, health care providers and researchers should be leveraging social media and smartphones as a way to help people. “There are people with mental illnesses who are experiencing debilitating symptoms and can’t leave their home,” she says. “Social media could be a safe platform to help people connect with others as a first step.”

Facebook, for one, says it shares that hope. The social network has wellness researchers who pay close attention to these findings and work to redesign the Web site’s interface with healthiness in mind, according to a company representative. “We want people to be healthy users of social media and that includes connecting in a meaningful way with your friends and community on Facebook. This is something we think a lot about, and research is core to our efforts,” Facebook’s director of research, David Ginsberg, wrote in an e-mailed response to queries.

In some cases users should be mindful of ways technology might be hurting rather than helping them—but the crux of the matter is in how one uses it, Shakya says. Reaching out for support from friends on Facebook or even using the multitude of fitness or mental health apps may have significant benefits. “This isn’t black and white,” she says. “It’s important to think about this stuff in nuance. It’s not like social media is terrible and ruining the world.”

Teenagers recognize this, too. “[The pros] are connecting to your friends immediately and being able to talk to them and share your ideas in a public way. If you want to say or advocate for something, it’s easy to share to everyone, and people will see it,” Aashima says. “It is very powerful. You can use it for good, and you can use it for bad.”