Impact of duration of screen time use on adolescent wellbeing in Scotland

Background: Social media and internet use is ubiquitous amongst young people today, yet it’s impact on adolescent wellbeing is not fully understood. This study assessed the extent to which daily screen-time was associated with mental wellbeing in Scottish schoolchildren. Methods: The Health Behaviour in School-aged Children (HBSC) 2017/18 survey is representative of 11, 13, and 15 year olds in Scotland. The primary exposure was daily screen-time during weekdays (≤2 hours, 3-5 hours, and >5 hours). Secondary binary measures included intensive online communication, and preference for online social interaction. The WHO-5 wellbeing index was used to assess mental wellbeing. Multilevel mixed effects regression models were used, adjusted for sociodemographic factors, exercise frequency and, for 13 and 15 year olds, sleep duration and quality. Results: There were 5,286 pupils from 208 schools in Scotland who participated. Mean wellbeing was lower in girls than boys (55 vs 60, p<0.001). Girls reported greater daily screen-time; 18% girls spent >5 hours (n=486), and 16% of boys (n=416), p=0.025. Mental wellbeing was lower in the heaviest users (>5 hours), with a difference of 15% amongst girls and 8% amongst boys (p<0.001) when compared to the lightest users (≤2 hours daily). In the adjusted models, this improved to a 6% difference for girls and 3% for boys. For older boys and girls, sleep duration and quality completely attenuated the association. Conclusions and implications: Longer daily screen-time duration was associated with small reductions in wellbeing in Scottish adolescents, however the association was attenuated by sociodemographic factors, exercise, and sleep.