LOS ANGELES, Calif. (CBS Local) – A study of teens using high-tech devices has found a link between constant use of digital media and ADHD.

According to scientists at USC, teens who are “heavy users” of digital devices like smartphones were twice as likely to show symptoms of attention-deficit/hyperactivity disorder than adolescents who only use the gadgets occasionally.

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“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,” Adam Leventhal, professor of preventive medicine and psychology at USC said in a press release.

Researchers examined nearly 2,600 public school students in Los Angeles County from 2014 to 2016 and tracked how often they used “14 popular digital media platforms.”

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The study, published in the Journal of the American Medical Association, discovered that 9.5 percent of the students who used half of the tested platforms had developed ADHD. Over 10 percent of the teens that reported using all of the platforms were found to have ADHD symptoms.

Less than 500 students reported being infrequent users of digital media. Among those teens, only 4.6 percent of the students had been diagnosed with attention deficit disorder.

“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,” Leventhal added.

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The USC team said they focused the two-year study on 15 and 16-year-olds because adolescence was a common point for the onset of ADHD and was also the point where children normally get “unfettered access to digital media.”