Ylva Trolle Lagerros, physician at the Obesity Centre in Stockholm who is currently researching the impact of lifestyle on health and future morbidity at the Department of Medicine, Solna at Karolinska Institutet, was quite convinced a few years ago that more screen time is associated with less physical activity – and that this could partly explain the high rates of obesity in socially deprived areas, where children usually have less scheduled sporting activity. To see whether the hypothesis was correct, she and her colleagues conducted a small study of 121 pupils in compulsory school grades 4 through 9 at two schools in widely different socioeconomic areas. In one school, 31% of the children were overweight.

“What sets our study apart from many others is that we have objective measures of physical activity and screen time rather than self-assessments,” she says.

The results Ylva Trolle Lagerros obtained were not at all what she expected.

“We could not see any link between physical activity and screen time. Physical activity did not compete with screen time. Nor was there more screen time in the lower socioeconomic area,” she states.

Moreover, there was no link between parents' screen time and that of children.

“So, it does not seem to be what we do as parents that is important. Our teenagers are growing up in a culture where there is a lot of screen time, and that time is hard to overcome,” she says.

However, the boys had five times more screen time in the form of gaming than the girls.

“We also saw that the girls were more physically active than the boys,” states Ylva Trolle Lagerros.

When she asked the children if they were satisfied with their screen time or if they wanted to increase or decrease it, she found more differences between boys and girls. The girls were either satisfied or wanted to reduce their screen time, while for the boys it was the other way around.

The study is small, and Ylva Trolle Lagerros wants to be underscore that more large-scale studies are needed to verify the results. Unlike Gisela Nyberg's larger study, she did not examine the fitness level of the children.

Swapping social media for physical activity improved mental health

The complexity of the relationship between screen use and poor mental and physical health is revealed in another study involving Mats Hallgren. In it, researchers followed several thousand teenagers for five years and, as expected, found that physical activity declined while poor mental health rose. In a follow-up study, the researchers looked at what happened after they asked participants to swap one hour of screen time for one hour of physical activity.

“In our study, swapping an hour of social media use for an hour of exercise was associated with improved mental health – the effect was strongest in girls and most apparent in those who exercised in groups,” he says.

In contrast, replacing an hour of computer games with exercise had no such effect. Mats Hallgren says that experimental studies are now needed to answer the question of what happens in young people's brains with different types of screen usage.

In cases where there is increased vulnerability, the health challenges are likely to be greater – and the risks of poor health higher, Anders Nilsson believes. One of his ongoing studies on screen habits and excessive computer use is based on children and young people between the ages of 12 and 17 who are enrolled in Child and Adolescent Psychiatry Services (BUP).

“In addition to seeing whether there is a link between screen habits and excessive computer gaming and mental health, we will investigate whether these children's habits differ from a non-clinical group,” he says.

He is also conducting a study using the twin registry to find out how environmental factors can influence the risk of computer gaming having negative consequences.

“I want to find out how much of the time spent gaming is due to genes, and how much is explained by environmental factors. This is a relatively unexplored field,” he says.

Children with ADHD are at extra risk for gaming disorder

Today, research by Lisa Thorell shows that there is a clear link between ADHD and excessive computer gaming. In an as yet unpublished study, she followed children with an early ADHD diagnosis from preschool to grade 6 of compulsory school.

“19% of children with ADHD met the criteria for gaming disorder, compared to 2% in the control group,” she says.

There may be neuropsychological as well as psychosocial reasons behind this.

“There is a lot of evidence suggesting that children with ADHD are at extra risk because of the fast-paced rewards of games and social media. It suits their personality,” she says.

But children with an early diagnosis also have more peer problems than others, find it difficult to participate in extracurricular activities, and often do not do well at school,” explains Lisa Thorell. Then, computer gaming becomes a way to relax and unwind.

“Many parents report that their children's gaming is an escape. But we have also seen that parents who have children with ADHD are more positive about gaming, because it adds something positive to their children's lives,” says Lisa Thorell.

Today, research is not able to keep up with technological developments, and it is difficult to do studies over a long period of time as new forms of gaming and social media are constantly emerging.

“It is currently difficult to say with certainty what the risk factors are – and how to intervene early and prevent them,” says Lisa Thorell.