Maartje Boer

SUMMARY AND DISCUSSION 299 9 induces upward social comparisons due to the abundance of idealized self- portrayals of others on social media (Twenge, 2019; Underwood & Ehrenreich, 2017; Verduyn et al., 2020). However, our findings suggest that these adversities do not emerge simply by using social media intensively. The discourse that high screen time is an indicator of risky behavior may be obsolete nowadays, given that social media are omnipresent in adolescents’ daily lives and intense SMU could be considered as rather normative (Anderson & Jiang, 2018; Smahel et al., 2020). Instead, adverse SMU effects seem to be driven by the unique characteristics of problematic SMU, such as having diminished control over thoughts, emotions, and behaviors due to SMU, or having conflicts with others due to SMU. By contrast, adolescents engaging in higher SMU intensity (without SMU problems) may be well able to regulate their use and to combine it with important activities. Accordingly, our findings showed that intense users reported more friends support than non-intense users (Chapter 4), that increases in SMU intensity were associated with concurrent increases in face-to-face contact with friends (Chapter 6), and that subgroups of adolescents reporting high SMU intensity showed higher levels of friendship competencies than subgroups reporting lower and average SMU intensity (Chapter 7). Similarly, other researchers found that adolescents reporting daily SMU spent more time with friends in the evenings than those who did not report daily SMU (De Looze et al., 2019). Together, these findings challenge the displacement hypothesis, which postulates that SMU harms adolescents’ wellbeing, because it goes at the expense of offline social interaction and the quality of friendships (Twenge, 2019; Twenge & Campbell, 2018; Underwood & Ehrenreich, 2017). Instead, in line with the stimulation hypothesis (Valkenburg & Peter, 2007, 2011), high SMU intensity may be an indicator of social involvement with peers, rather than impaired (social) wellbeing. After all, social media allow adolescents tomaintain and strengthen friendships, for instance by facilitating sharing feelings or worries with friends (Valkenburg & Peter, 2009; Verduyn et al., 2017). In addition, the finding that lower wellbeing (on the between-person level) predicted SMU problems (Key finding 4; Chapter 7) supports theory on the emergence of problematic internet-related behaviors. According to the cognitive behavioral model , pre-existing psychological problems drive certain