Maartje Boer

THE COURSE OF PROBLEMATIC SMU 193 7 The Course of Problematic Social Media Use in Young Adolescents: A Latent Class Growth Analysis The current generation of young adolescents grow up in a ‘hybrid’ world, where their offline world is intertwined with online contexts that are facilitated by social media, such as Instagram and Snapchat. Between 2017 and 2019, 63% of 12- to 14-year-old and 77% of 15- and 16-year-old European adolescents reported daily usage of social media (Smahel et al., 2020). Other research shows that in 2017 and 2018, a large share of 13- and 15-year- old European adolescents reported that they were interacting online with friends and others almost all the time throughout the day (36% and 41%, respectively) (Inchley et al., 2020b). From a developmental perspective, it is understandable why social media are so popular among early and middle adolescents (Granic et al., 2020). Social media allow young adolescents to form and maintain peer relationships (e.g., through instant messaging), to share their perspectives, narratives, and self-portrayals with others (e.g., by uploading personal photos, videos, and texts), to receive feedback on their appearances and online behaviors (e.g., through ‘likes’ and responses from peers), and to learn from others (e.g., by browsing through peers’ uploads). These functions are all crucial for identity development: a core developmental task of young adolescents (Erikson, 1968). However, for some of adolescents, social media use (SMU) deviates from normative adolescent behavior, namely when they experience symptoms of addiction to social media. In that case, adolescents cannot regulate their SMU: They have social media on top of their mind constantly, feel stress or anxiety when SMU is not possible, and/or report that their SMU interferes with their functioning in important life domains (Andreassen, 2015; Griffiths et al., 2014). The presence of such addiction symptoms is considered harmful (Griffiths et al., 2014). For instance, meta-analytic findings indicate that adolescents with such symptoms report low wellbeing (Marino et al., 2018b). Furthermore, several longitudinal studies, including studies based on data from the present study, suggest that symptoms of addiction towards SMU increase mental health problems, such as depressive symptoms, psychological distress, and attention deficits (Boer, Stevens, et al., 2020; Boer, Stevens, Finkenauer, De Looze, et al., 2021; I. H. Chen et al., 2020; Raudsepp, 2019). Nevertheless, social