Smartphone use, wellbeing, and their association in children.

Background: This study assessed changes in the duration of smartphone use, problematic smartphone use (PSU), quality of life, and their association from 2018 to 2024 in children and adolescents.

Methods: Data were collected between 2018 and 2024 within the LIFE Child cohort study (Germany). We used a repeated cross-sectional dataset containing 2576 data points of 1113 10- to 17-year-old children and adolescents (51% male) who had reported on their quality of life, PSU, and their smartphone use duration. Hierarchical regression analyses were applied to assess associations of PSU, smartphone use duration, and quality of life with the year of assessment and associations of PSU and smartphone use duration with quality of life.

Results: From 2021 onwards, symptoms of PSU and smartphone use durations >3 h/day were significantly more frequent than in 2018. For PSU, these changes were significantly stronger in girls and younger children. Concurrently, quality of life was significantly poorer than in 2018. Both PSU and long smartphone usage durations were significantly associated with lower quality of life.

Conclusions: This study shows the increasingly problematic use of smartphones and its negative association with the overall declining quality of life of children over the last seven years.

Impact: Problematic smartphone use in children and adolescents has increased in the last seven years, while quality of life has decreased. Problematic smartphone use is associated with decreased quality of life, and this association was especially strong in 2022 and 2023. In contrast to previous studies, the present time trend analysis covers time periods before and within the Covid-19 pandemic and suggests that the pandemic has reinforced the observed changes in smartphone use and quality of life. Restricting children's smartphone use might help to improve or maintain a higher quality of life.