Childhood diagnoses of ADHD or attention deficit hyperactivity disorder have risen sharply in recent years, making trying to understand the causes of the disorder especially important. A new study from the University of Southern California suggests one likely culprit, at least for teens: the amount of time they spend on social media.

Social media has certainly changed the way people — of any age —spend time online. “What’s new is that previous studies on this topic were done many years ago, when social media, mobile phones, tablets and mobile apps didn’t exist,” said study author, Adam Leventhal, in a news release. “New, mobile technologies can provide fast, high-intensity stimulation accessible all day, which has increased digital media exposure far beyond what’s been studied before.”

About 10 percent of the students who used social media platforms frequently developed ADHD. But less than five percent of those whose level of use was low developed the disorder.

The study design was simple: The team recruited 15- and 16-year-old kids without ADHD, and asked them about their social media use. They grouped them as having low, medium or high social media use.

Then, they followed up with the participants over the next two years, and took note of how many developed ADHD by the 12th grade. The team found that about 10 percent of the students who used social media platforms frequently developed ADHD. But less than five percent of those whose level of use was low developed the disorder.

“We can’t confirm causation from the study, but this was a statistically significant association,” Leventhal explained. “We can say with confidence that teens who were exposed to higher levels of digital media were significantly more likely to develop ADHD symptoms in the future.”

According to the CDC, about six percent of children in the U.S. have been diagnosed with ADHD, which may help put the new study into context. Using social media sparingly may be the wisest approach. Heavy use can raise one’s risk considerably above average.

Again, the study, published in the Journal of the American Medical Association, doesn't show that media use causes ADHD, but the connection is pretty clear. Other studies have reported that heavy social media use is also linked to depression and anxiety, which also have connections to ADHD.

It may be a chicken-or-egg question: Social media use may raise the risk for ADHD, or people who are already predisposed or are having early symptoms may seek out social media as a result. And it may be a little bit of both.

In any case, less social media use is probably better for teens’ mental and emotional well-being. The same connection is likely true for younger kids, but that needs to be illustrated in a future study.

Says Leventhal, “This study raises concern whether the proliferation of high-performance digital media technologies may be putting a new generation of youth at risk for ADHD.”

Parents should encourage kids to connect in person as much as possible, rather than online. That’s probably good advice for adults, too.