Maartje Boer

SMU AND WELLBEING ACROSS COUNTRIES 103 4 Adolescents’ Intense and Problematic Social Media Use and Their Wellbeing in 29 Countries Social media use (SMU) has become increasingly embedded in adolescents’ daily lives inrecentyears, leadingtoconcernsabout itspotential impact (Primack & Escobar-Viera, 2017; Underwood & Ehrenreich, 2017). In the United States, the percentage of adolescents that reports being online almost constantly has increased from 25% to 45% between 2015 and 2018 (Anderson & Jiang, 2018). In addition, two large-scale studies among European adolescents, conducted in 2014 and 2015, showed that the prevalence of addiction-like problematic SMU was4.5%(Bányai et al., 2017) and9.1%(Mérelleet al., 2017). Other thanadolescents who merely show intense SMU by spending a lot of time on SMU, adolescents with problematic SMU typically have a diminished ability to regulate their SMU impulses, feel discomfort such as stress or anxiety when SMU is restricted, and have SMU on top of their mind constantly (Griffiths et al., 2014). Research suggests that intense SMU is linked to lower mental (Kelly et al., 2018; Primack & Escobar-Viera, 2017; Twenge, Joiner, et al., 2018), school (Al-Menayes, 2015b), and social wellbeing (Underwood & Ehrenreich, 2017) of adolescents. Moreover, problematic SMU is also associated with lower adolescent wellbeing (Marino et al., 2018b). However, important gaps in knowledge remain, three of which we address in this study. First, intense and problematic SMU are distinct concepts, yet correlated (Boer, Stevens, et al., 2020; Van den Eijnden et al., 2016, 2018), but studies typically have not examined their associations with wellbeing simultaneously in one model. Therefore, it remains unclear whether intense and problematic SMU are as strongly associated with lower adolescent wellbeing. Second, existing research on intense and problematic SMU and their outcomes has typically used single-country data. Hence, it is not clear whether and to what extent the associations with wellbeing apply cross-nationally. Third, little is known about the extent to which adolescents’ intense and problematic SMU differs across countries. The present study addresses these gaps by investigating independent associations of intense and problematic SMU with wellbeing across 29 countries. Several mechanisms have been proposed for the negative associations of intense and problematic SMU with wellbeing. Intense users may be excessively exposed to unrealistic portrayals of others, which, in turn, may elicit