Maartje Boer

CHAPTER 1 10 about problematic SMU , which also has been defined as social media addiction, social media disorder, or compulsive social media use (Lee et al., 2017) . Problematic SMU is conceptually different from the intensity of SMU, because problematic SMU is characterized by symptoms of addiction to social media, whereas the intensity of SMU refers to nothing more than the time spent (e.g., hours per day) or frequency of SMU (e.g., number of times viewing per day). Although it is common that adolescents use social media intensively (Anderson & Jiang, 2018; Smahel et al., 2020), scholars consider problematic SMU as exceptional behavior (Griffiths, 2013; Kardefelt-Winther et al., 2017). In line with this suggestion, a meta-analysis using samples across 32 nations estimated the average prevalence rate of problematic SMU at 5% at the population level, although this rate varied by demographic variables, whereby samples with young respondents showed higher rates than samples with adult respondents (Cheng et al., 2021). Other international research among adolescents reports a prevalence rate of 7%, with (small) differences by gender and age (Figure 1.2; Inchley et al., 2020b). In short, adolescents who display problematic SMU are incapable of regulating their use and/or have social media on top of their mind constantly (Griffiths et al., 2014). Problematic usersmay be ‘addicted’ to the social rewards of SMU, such as the involvement with peers and other people by monitoring them online, and the reassurance to be noticed by others by posting personal content on social media (Veissière & Stendel, 2018). Problematic SMU is often defined by six addiction criteria that parallel substance-related addiction criteria, including being preoccupied with social media by constantly thinking about it, using social media to escape from negative feelings, increasing tolerance levels by wanting to use social media more and more to achieve satisfaction, experiencing withdrawal symptoms when SMU is not possible, having conflicts with, for example, close relationships due to excessive SMU, and engaging in persistent SMU by being unable to control SMU (Andreassen et al., 2012; Bányai et al., 2017; Kuss et al., 2014). Yet, unlike other non-substance related addictions, including gambling and internet gaming addiction, neither the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) nor the International Classification of Disease (ICD-11) recognize a behavioral addiction related to SMU (American Psychiatric Association, 2013; World Health Organization, 2019). This is understandable, because social media became