Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent psychiatric disorder in adolescence and results severe impairment. Few psychosocial interventions aim at ADHD in adolescence and are rarely evaluated in randomized controlled trials (RCTs). Therefore, an intervention combining adolescent-directed problem-solving and…

Recent research indicates that the development of antisocial behavior among students is influenced by the behavioral characteristics of their classmates. However, not all peers in a given class may exert the same influence. Thus, we examined the extent to which individual development is predicted by the perceived proportion of all students with…

Starting from a person-environment fit framework, this study investigates whether ethnic congruence--the percentage of co-ethnics in a school--relates to school misconduct and whether congruence effects differ between ethnic minority and majority students. Moreover, we investigate whether eventual associations are mediated by friendship…