Teenagers who spend too much time glued to digital devices are more prone to developing attention-deficit/hyperactivity disorder, according to a USC study released today.

According to the study, appears in the Journal of the American Medical Association, teens who are heavy users of digital devices are twice as likely as infrequent users to show symptoms of ADHD.

The study, which tracked nearly 2,600 teenagers for two years, focuses on the mental health consequences of using various digital platforms, including social media, streaming video, text messaging, music downloads and online chatrooms. Authors said it differs from previous research that linked TV and video games to the illness.

“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 Adam Leventhal, professor of preventive medicine and psychology and director of the USC Health, Emotion and Addiction Laboratory at the Keck School of Medicine. “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.”

In the study, USC scientists began with 4,100 eligible students, ages 15 and 16, across 10 public highs schools in Los Angeles County that represented mixed demographic and socioeconomic status. Leventhal said the researchers focused on teens because adolescence marks a moment for ADHD onset and unfettered access to digital media.

The study was then pared to 2,587 participants by removing students for preexisting ADHD symptoms, with a goal of starting with a clean slate to focus on occurrence of new symptoms over the two-year study.

The researchers asked students how frequently they used 14 popular digital media platforms and sorted the frequency into three categories: no use, medium use and high use. The students were monitored every six months between 2014 and 2016 to determine if digital media use in 10th grade was associated with ADHD symptoms tracked through 12th grade.

The study found that 9.5 percent of the 114 children who used half the digital media platforms frequently and 10.5 percent of the 51 kids who used all 14 platforms frequently showed new ADHD symptoms. By comparison, 4.6 percent of the 495 students who were not frequent users of any digital activity showed ADHD symptoms, which USC said is approximate to background rates of the disorder in the general population.

“We can’t confirm causation from the study, but this was a statistically significant association,” Leventhal said. “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.”

He added, “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.”