Sleep Health | Sleep Review
School-aged children who spend more time in front of screens are only marginally more likely to have attention disorders, sleep disorders, or poorer grades and no longer suffer from depression and anxiety, finds one of the largest studies to date to find out how screen time affects adolescents.
The study, published September 8 in the journal PLOS ONE, also showed a potential benefit of the often-maligned devices: children who spent more time with screens had more close friends.
“These results suggest that we should watch out for screens, but that screen time is unlikely to be inherently harmful to our youth,” says lead author Katie Paulich, a PhD student at the Department of Psychology and Neuroscience, in a press release.
For the study, Paulich and colleagues at the Institute for Behavioral Genetics evaluated data from the ongoing Adolescent Brain and Cognitive Development study, the largest long-term study on the health and development of the brain in children ever carried out in the United States.
They analyzed information from a diverse national sample of 11,800 9- and 10-year-olds, including screen time questionnaires, parenting reports on behavior problems and grades, and mental health ratings.
On average, boys spent about 45 minutes more per day with screens than girls, reaching almost five hours a day on weekends and four hours on weekdays.
Boys and girls used screens differently, with boys spending twice as much time playing video games while girls spending more time on social media. (The data collected prior to the COVID-19 pandemic did not include screen time related to homework or online learning).
Like previous, smaller studies, the research found that children who spent more time in front of screens tended to sleep worse, get lower grades, and exhibit more “externalizing” behaviors (things like ADHD, conduct disorder, and oppositional defiance disorder).
But when compared to other factors that shaped her life, the impact of screen time was tiny.
For example, a child’s socio-economic status had a 2.5 times greater impact on such behavioral outcomes. Of all the influences assessed, screen time only accounted for about 2% of the differences between children in the measured results.
“A number of publications in recent years have suggested that screen time could be harmful to children, but there have also been a few reviews suggesting that these negative effects have been overestimated,” says senior author John Hewitt, director of the Institute for Behavioral Genetics. In a press release, “Using this extensive set of data, we found that while there are relationships between screen time and negative results, they are not big and not bad.”
While the study found a link between screen time and some mental health and behavior problems, Paulich points out that it doesn’t mean that it was caused by it. In fact, the opposite could be the case.
For example, parents with children who are prone to aggressive behavior or lack of attention might be more likely to sit them down with a video game. Children who cannot sleep for other reasons may use their smartphones to pass the time.
While more research is needed, the type of screen time you have is more important than the amount, Paulich says. For example, previous research has shown that video games played with others can foster relationships, especially with boys (who are more likely to play them), while binge-watching shows alone can have negative consequences.
Because the new study only looked at adolescents aged 9 and 10, the results do not necessarily apply to older children. The researchers aim to follow the group over time.
The American Academy of Pediatrics has guidelines for screen time for children under the age of 5, but the authors note that there is not yet an empirically established threshold for what an “acceptable level” of screen time for older children is.
“The picture is unclear and depends on which devices, which activities, what is being suppressed and, I strongly suspect, on the characteristics of the child,” says Hewitt.
For now, the father of four says: “I would advise parents not to worry too much that their children spend a few hours a day on their devices.”
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