Esther Mertens

| 11 General Introduction identity formation as these can influence how experiences and memories are processed (Haviland, Davidson, Ruetsch, Gebelt, & Lancelot, 1994). Second, adolescents are becoming more aware of others while spending more time outside the home encountering varying contexts in which they need to interact with others, such as the school, occupational, and romantic contexts (Barber, 2005). Adolescents’ ability to positively engage in interactions and constructively manage social situations is stimulated by their level of awareness of social norms and cues, and understanding that others may not have the same thoughts and feelings as they do (Shek & Leung, 2016). Hence, adolescents’ psychosocial development can benefit from enhancing their competencies and preventing development of problems in both the intra- and interpersonal domains. The school environment has been recognized as a powerful context to address adolescents’ intra- and interpersonal domains (Pellegrino & Hilton, 2012). Schools have the responsibility to actively cultivate their students’ attitudes, values, and social support in addition to stimulating students’ academic development (Langford et al., 2014; World Health Organization, 1995). Given that adolescents spend a lot of their time at school, it also creates a perfect opportunity to involve adolescents in an intervention by implementing it during school hours (Langford et al., 2014). This is especially beneficial for those interventions that aim to involve a group of adolescents that are more difficult to reach outside the school context (Liber, De Boo, Huizenga, & Prins, 2013). In the Netherlands there are three educational tracks in secondary school, starting at 7 th Grade: Preparatory vocational track (prevocational track), preparatory college track, and preparatory university track. Compared to students in the preparatory college and university tracks, prevocational students report higher levels of behavioral problems (20% versus 13% and 7%), have more problems with peers (20% versus 10% and 8%; Stevens & De Looze, 2018), and are more likely to engage in risk behaviors (e.g., binge-drinking: 48% versus 37% and 25%; smoking: 17% versus 5% and 2%; Harakeh, De Looze, Schrijvers, Van Dorsselaer, & Vollebergh, 2012). These increased risks for psychological and behavioral problems indicate the necessity of effective interventions for this group of students, as more than half (54%) of the entire Dutch student population follows this prevocational track (Central Bureau for Statistics, 2020). However, prevocational students are a challenging group to involve in an intervention. They generally show lower levels of autonomy, show less intrinsic motivation for school and (verbal) learning, and have lower cognitive capacities compared to students following the other two tracks (Timmermans, Naaijer, Keuning, & Zijsling, 2017). These characteristics suggest that prevocational students might require a specific intervention approach that fits in well with their learning processes to be able to fully benefit from an intervention. The main aim of this dissertation was to study whether and under what circumstances universal interventions in secondary schools can successfully stimulate students’ competencies and prevent problems in the intra- and interpersonal domain. 1