Forced displacement is at a historical high point, with over 123 million people estimated as being forcibly displaced in 2024. Adolescents make up the majority of this population. Although Sweden has recently seen the lowest number of asylum applications since the 1990s, it has for a long time been an important resettlement country for those forcibly displaced, and many adolescents with refugee backgrounds who fled to Sweden in the last decade still reside there. Beyond sharing the experience of having to flee, adolescents with refugee backgrounds are a diverse population, with experiences before, during, and after migration differing significantly.

Research on violence and its consequences among adolescents with refugee backgrounds is growing and shows that violence exposure and poor mental health is prevalent within the population. However, several research gaps still exist. First, prevalence rates for mental disorders are noticeably heterogeneous between studies, even after methodological differences are accounted for, and research rarely captures mental health as a unified concept consisting of functioning, well-being, and symptoms. Second, complex posttraumatic stress disorder (CPTSD) remains understudied in terms of validity, prevalence, and risk factors, despite indications that the diagnosis may be of particular relevance for the population. Third, data on violence exposure often overlook specific forms of violence, such as child maltreatment, and studies rarely report exposure across different migration phases. Fourth, the potential differential impact of violence exposure in different migration phases, and the influence of polyvictimisation, on mental health are poorly understood.

This thesis aimed to bridge these gaps and provide a better understanding of patterns of violence exposure and mental health among adolescents with refugee backgrounds. To do so, a systematic review mapped the use of person-centred statistical methods in research on violence exposure and mental health within the population (Study I). Furthermore, in a Swedish community sample of adolescents with refugee backgrounds (N = 296), person-centred statistical analysis was used to explore mental health subgroups (Study II) and to examine the prevalence, validity of, and risk factors associated with CPTSD (Study III). Finally, structural equation modelling along with descriptive statistics was used to investigate the prevalence of violence exposure across migration phases and their associations with mental health outcomes (Study IV).

The findings showed that mental health subgroups based on general functioning, well-being, and trauma symptoms can be a theoretically meaningful and clinically useful way of describing heterogeneity in mental health. Additionally, the findings demonstrated a high prevalence of CPTSD and provided further validity of the diagnosis. Child maltreatment and polyvictimisation were identified as significant risk factors for poor mental health. Furthermore, the results revealed a high prevalence of violence exposure across all phases of migration, with certain types and forms of violence, as well as polyvictimisation, being particularly prevalent. Additionally, the timing of violence exposure was found to be associated with mental health outcomes: early exposure was related to trauma symptoms while later exposure was more associated with general functioning and well-being. Additional factors beyond violence also played a significant role, with asylum and unaccompanied status found to be equally as strongly associated with mental health outcomes as violence exposure.

These findings offer nuance in describing adolescents with refugee backgrounds, challenging narratives of vulnerability. Mental health subgroups can inform professionals about the type of intervention to offer and where to deliver it, and may play a role in designing interventions or evaluating the effectiveness of existing ones. The high prevalence of CPTSD emphasises the importance of addressing barriers to care for adolescents with refugee backgrounds and developing clinical guidelines for the diagnosis. Finally, improving public policies to increase security and safety may be essential to address both violence exposure and other stressors and, subsequently, improve mental health among adolescents with refugee backgrounds.