Maartje Boer

CHAPTER 2 28 latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM- 5) added gambling disorder to the ‘substance-related and addictive disorders’- category and internet gaming disorder as a condition requiring further study, whereby both behavioral addictions are defined by the core criteria of addiction and a few additional criteria (American Psychiatric Association, 2013). Unlike gambling and gaming disorder, the DSM-5 does not acknowledge social media disorder as a (tentative) behavioral addiction. However, SMU is a relatively new behavior, that increased especially after the rise of smartphone use around 2012 (Twenge, Martin, et al., 2018), when the development of the DSM-5 was already in progress. It generally it takes several decennia before disorder classification systems acknowledge the existence of newdisorders. Scholars argue that people can experience SMU-related addiction symptoms that parallel substance- related addiction symptoms, and that social media addiction results from the same ‘biopsychosocial’ processes that drive substance-related addictions (Griffiths, 2013; Griffiths et al., 2014; Kuss & Griffiths, 2011). Furthermore, there is increasing evidence that the presence of these symptoms impair adolescents’ cognitive and psychosocial functioning (Boer, Stevens, et al., 2020; Boer, Stevens, Finkenauer, De Looze, et al., 2021; Van den Eijnden et al., 2018). In absence of a formal recognition of social media disorder as a behavioral addiction, we refer to it as ‘problematic SMU’. Researchers have used several instruments to measure problematic SMU, but most instruments have not been validated (Andreassen, 2015). To our knowledge, the only instrument that has been validated in a large- scale representative adolescent sample is the Bergen Social Media Addiction Scale (BSMAS) (Andreassen et al., 2016; Bányai et al., 2017; Lin et al., 2017). The BSMAS has been developed parallel to the SMD-scale, and covers the six core criteria of addiction (Griffiths, 2005; Griffiths et al., 2014). Scholars have argued that the presence of addiction criteria in relation to (social media) behaviors is not necessarily indicative of whether the behavior is harmful, which is considered a crucial aspect for defining addiction-like behaviors (Kardefelt- Winther et al., 2017; Van Rooij et al., 2018). Therefore, the SMD-scale measures the same six core criteria of addiction and two additional criteria that refer to harmful implications due to SMU: problems (i.e., experiencing problems on important life domains due to SMU) and displacement (i.e., displacing social or recreational activities by SMU). The SMD-scale also includes deception (i.e.,