For kids already at risk for mental health issues like anxiety and depression, excessive screen time is linked to attention, behavioral and emotional problems, according to a new study published in Child Development.

Duke University researchers surveyed 151 adolescents between 11 and 15 years old about their daily technology use and looked for symptoms of mental health issues 18 months later. The kids were all of low socioeconomic status and already at risk for mental health problems, according to the study’s press release.

The researchers found that on days where the kids used their devices more than usual (compared to both their own use and their peers’ use) they were more likely to exhibit behavioral problems like lying or fighting. They also had a harder time paying attention and showed symptoms of attention deficit-hyperactivity disorder (ADHD).

Those negative effects seemed to last well beyond one-off screen-centric days: Researchers found that 18 months later, kids who spent the most time glued to tech had a harder time regulating their behavior and emotions.

On average, the study subjects reported spending 2.3 hours a day using digital technologies like smartphones and computers. More than an hour of that time was spent texting, the press release notes, with the kids sending a whopping 41 texts per day, on average.

Here’s where things get a little complicated (much like our relationship with technology). It’s possible that the kids were texting because they were experiencing symptoms of anxiety and depression and were seeking support, according to Candice Odgers, the study’s senior author and a professor at Duke’s Sanford School of Public Policy. If that was the case, “The findings suggest contemporary youth may be using digital technology to connect in positive ways versus isolating themselves,” the authors said in the press release.

There are a few caveats to note here. For one, the study proved correlation, not causation, meaning the researchers can’t say with certainty that screens caused these behavioral issues. Additionally, the study looked at adolescents who were already at risk for mental health problems, and it could be that these kids are simply more likely to spend too much time on devices.

Either way, study provides further insight into the growing body of research on the link between screens and adolescents’ overall health. The take home message? Screens may affect some of us more strongly than others, but we could all benefit from setting healthy tech boundaries.

Read more about the findings here.

Originally published at journal.thriveglobal.com