Decreases in smartphone overuse and moderators among adults in general after the COVID-19 outbreak: A three-year prospective study

The outbreak of the coronavirus disease 2019 (COVID-19) led many individuals to utilize digital devices, including smartphones, to minimize in-person activities. How the pandemic brought about a long-term impact on smartphone overuse is still unclear owing to mixed results of previous studies. This prospective study investigated whether levels of smartphone overuse increased over three years after the COVID-19 outbreak. Recruited through a research marketing company, 86,827 Japanese adults were deemed eligible to take part in this study and responded to three outcome measures of smartphone overuse and other measures related to smartphone use and COVID-19. Data collection occurred before the outbreak in December 2019 and at six subsequent time points between the first outbreak in Japan and December 2022. Contrary to the hypothesis, a growth model analysis (GMA) revealed downward trajectories in all three smartphone overuse measures: the Smartphone Addiction Scale, Short Version, GMA d = -0.13; smartphone overuse, GMA d = -0.14; and negative consequences from overuse, GMA d = -0.23. A complete case analysis suggested the robustness of these effect sizes. Moderators of the declines in all three outcome measures included spending less money on purchasing new apps and stronger beliefs about not having contracted COVID-19. As individuals turned to online platforms during the COVID-19 outbreak, high reliance on digital technologies, once perceived as overuse before the pandemic, may have become necessary preventive measures against the pandemic, resulting in diminished smartphone overuse.