STUDY FINDS
JYVÄSKYLÄ, Finland — In case you needed another reason to hold off on buying your child a phone, research shows a troubling connection between childhood screen habits and teenage mental well-being. The eight-year study, which tracked children from elementary school into adolescence, found that kids who racked up more screen time—especially on mobile devices—showed higher levels of stress and depressive symptoms as teenagers.
The study adds to the large body of research that should make parents think twice about unlimited device access, especially as more children experience mental health struggles at an early age. Between one-quarter and one-third of adolescents worldwide experience mental health problems, with symptoms typically first appearing during the teenage years. Researchers now have more concrete evidence about lifestyle factors that might help prevent psychological distress before it takes root.
Study authors used data from the Physical Activity and Nutrition in Children (PANIC) study, which followed 187 Finnish children over eight years, from ages 6-9 into their mid-teens. Researchers regularly checked in on their physical activity, screen time, sleep patterns, and eating habits. When these children reached adolescence (average age 15.8), the researchers assessed their mental health using standardized measures of stress and depression.
The data painted a clear picture: teenagers who had accumulated more total screen time and mobile device use throughout childhood showed significantly higher levels of stress and depressive symptoms. The connection between mobile device use and depression was particularly strong, showing a “moderate effect size”—substantial in behavioral research terms.
The team found that adolescents spent nearly five hours daily on screens, with over two hours on mobile devices alone. Many parents might find these numbers unsurprising, but the mental health correlations deserve attention.
Physical activity told the opposite story. Teens who maintained higher activity levels during childhood, especially in supervised settings like sports or structured exercise programs, showed better mental health outcomes. This protective effect remained significant even after researchers accounted for factors like parental education, body composition, and puberty status.
Gender differences added another dimension to the findings. For boys, physical activity showed stronger protective effects against stress than for girls.
Surprisingly, neither diet quality nor sleep duration showed strong relationships with teen mental health in this study. This doesn’t mean these factors aren’t important for overall health—just that screen time and physical activity may have more direct impacts on adolescent mental wellbeing.
For parents struggling with screen time battles, this research provides compelling evidence for setting reasonable limits. The findings highlight that mobile device use specifically—more than television or computer time—warrants special attention. With smartphones and tablets become increasingly central to education and social connections, creating healthy boundaries becomes more challenging but potentially more important.
The study, published in JAMA Network Open, also emphasizes the value of supervised physical activities. Children who participated in more structured exercise from ages 6-15 showed fewer mental health problems in adolescence. It’s all the more reason schools and community programs aimed at promoting youth mental health should find more ways to get children moving.
Most revealing were the outcomes showing that teenagers with both low physical activity and high screen time had the worst mental health outcomes. This demonstrates that addressing either factor alone might not be as effective as a balanced approach that both limits screen time and increases physical activity.
While conducted in Finland, the study’s findings likely apply to children in other developed countries with similar technology access patterns. As smartphone use continues rising globally, understanding its potential psychological impact grows increasingly urgent.
For families navigating the complex digital landscape, this research offers practical guidance: limit screen time (especially on mobile devices), encourage regular physical activity (particularly supervised activities like sports), and remember that these choices may affect not just current behavior but long-term mental health.
Mental health professionals and pediatricians may want to include screen time discussions in their preventive care conversations. Creating balanced digital environments and promoting consistent physical activity within supportive social contexts could become key strategies for protecting youth mental health.
Incorporating technology into children’s lives at younger ages is understandably commonplace these days. But here have another study showing why childhood habits matter. How we balance screens and physical activity today may shape the psychological landscape our children navigate tomorrow.
While this study provides valuable insights, several factors warrant consideration before drawing firm conclusions:
These limitations don’t invalidate the findings but suggest we should view them as part of a broader conversation about youth mental health rather than definitive proof.
The Finnish researchers designed a robust study to track children’s lifestyle behaviors over time. Starting with 504 children aged 6-9, they collected data at three points: baseline (2007-2009), 2-year follow-up, and 8-year follow-up (2015-2017). By the final assessment, 187 teens had complete data on self-reported behaviors and mental health. The team used both questionnaires and wearable devices to measure lifestyle factors. Children and parents reported physical activity and screen time through surveys, while researchers objectively tracked movement using devices combining accelerometers and heart rate monitors. Food diaries helped assess diet quality, which was scored using a Baltic Sea Diet measurement tool. To capture the cumulative effect of behaviors over eight years, the researchers calculated “area under the curve” measurements rather than looking at isolated time points. This method accounts for the entire pattern of exposure throughout childhood. When participants reached adolescence (around age 15.8), they completed two standard mental health assessments: the Cohen Perceived Stress Scale and the Beck Depression Inventory.
The findings revealed clear connections between childhood behaviors and teen mental health. Higher self-reported physical activity was linked to better mental health outcomes, with statistical relationships showing small but meaningful effect sizes (standardized coefficients between -0.14 and -0.17). Screen time showed even stronger relationships with mental health problems. Total screen time was associated with both stress (coefficient 0.27) and depressive symptoms (coefficient 0.30), representing moderate effect sizes. Mobile device use showed the strongest associations of all measured factors, with coefficients of 0.28 for stress and 0.33 for depression. Computer use was linked to stress but showed a weaker relationship with depression. The research revealed some interesting gender patterns: boys seemed to benefit more from physical activity in terms of stress reduction than girls did. Unexpectedly, diet quality and measured sleep duration didn’t show significant associations with mental health outcomes. The researchers also found that adolescents with both low physical activity and high screen time showed the highest levels of mental health symptoms, suggesting these factors may work together to impact psychological wellbeing.
The research team acknowledged several constraints that might affect how we interpret their findings. Their final sample size of 187 participants limits statistical power, especially when analyzing differences between boys and girls. Many potential participants dropped out during the eight-year study period, which could skew results if those who left differed systematically from those who stayed. While the researchers used advanced methods to measure cumulative exposure to different behaviors, their approach might not capture short-term fluctuations between measurement points. The study didn’t assess important contextual factors, such as the specific content of screen time or the social aspects of physical activities. Since the follow-up ended in 2017, the findings may not fully apply to current technology patterns, particularly given rapid changes in social media platforms. Although the researchers measured sleep duration, they didn’t assess sleep quality or how long it took participants to fall asleep—factors that might have different relationships with mental health. Finally, while the study shows correlations between lifestyle behaviors and mental health, it can’t prove that one directly causes the other.