Social media could be draining children of their ability to concentrate, a new study says.

Children who spend a lot of time on Instagram, Snapchat, TikTok, Facebook, Twitter, or Messenger gradually become less able to focus and pay attention, researchers reported Dec. 8 in the journal Pediatrics Open Science.

This might partially explain why ADHD diagnoses have increased among kids in recent years, researchers said.

"Our study suggests that it is specifically social media that affects children's ability to concentrate," said senior researcher Torkel Klingberg, a professor of cognitive neuroscience at Karolinska Institutet in Sweden.

"Social media entails constant distractions in the form of messages and notifications, and the mere thought of whether a message has arrived can act as a mental distraction," Klingberg said in a news release. "This affects the ability to stay focused and could explain the association."

For the new study, researchers tracked more than 8,300 U.S. children ages 9 to 10 for four years.

The kids regularly reported how much time they spent on social media, watched TV or videos, or played video games. Parents provided assessments of their children's levels of attention, hyperactivity and impulsiveness.

During the study, average time on social media rose from about 30 minutes a day for 9-year-olds to 2.5 hours for 13-year-olds, results showed.

Researchers found that even average social media use blunted children's ability to concentrate, and the effect grew over time.

Additionally, kids who already had trouble paying attention did not start to use social media more. That suggests that social media use leads to difficulty focusing rather than vice-versa, researchers said.

No link was found between lack of attention and children watching television or playing video games.

Further, the link between lack of attention and social media was not influenced by a child's socioeconomic background or any genetic predisposition they had toward ADHD, researchers found.

Researchers also found no increase in hyperactive or impulsive behavior, another hallmark of ADHD.

"Greater consumption of social media might explain part of the increase we're seeing in ADHD diagnoses, even if ADHD is also associated with hyperactivity, which didn't increase in our study," Klingberg said.

Researchers plan to continue following the children to see if the association remains through their teen years.

"We hope that our findings will help parents and policymakers make well-informed decisions on healthy digital consumption that support children's cognitive development," lead researcher Samson Nivins, a postdoctoral researcher at Karolinska Institutet, said in a news release.

The study was conducted in conjunction with researchers at Oregon Health & Science University in Portland.