Criminology has a long tradition of examining risk factors for youth offending. Mental health problems (MHPs) have been recognised as an important risk factor in this context, with externalising problems in particular having being highlighted as highly significant. However, questions remain regarding the nature of the associations between MHPs and youth offending, for example with regard to their development, gender differences, and the role of associations with contextual variables. To better understand the relationship between MHPs and youth offending, further research is needed using a comprehensive perspective that takes into account the multidimensional nature of MHPs, differences between different types of MHPs, developmental changes over time, interactions with contextual factors, and gender differences. 

The aim of this thesis has been to extend the knowledge and contribute to a more comprehensive understanding of the associations between MHPs and youth offending by using longitudinal, community-based data from the Malmö Individual and Neighbourhood Development Study (MINDS). Study I examines how differences in MHPs are associated with differences in involvement in crime among adolescents, as well as how individual changes in mental health are associated with changes in involvement in crime over time. Study II examines girls’ offending on the basis of  three research questions looking at: (1) whether MHPs are more common among teen girls who report having committed offences compared to those who do not report offending, (2) how different types of MHPs are associated with offending, and (3) whether these associations are affected when we adjusted for the parent-child relationship, parental monitoring, and peer relationships. Study III examines the associations between different subtypes of negative life events (NLEs), MHPs, and youth offending, as well as whether the effects of youth NLEs on offending are mediated by a potential association between NLEs and MHPs. Study IV examines whether receiving professional support for mental health problems during adolescence is associated with the likelihood of subsequent offending.  

The overall findings from the thesis suggest that there are important associations between MHPs and youth offending, but that these associations are complex and may differ between individuals depending on the types of MHPs in question, gender, comorbidity, and interactions with contextual factors. The thesis highlights the importance of considering the associations between MHPs and youth offending in the context of support and prevention strategies as a means of more effectively hindering negative development, which will both benefit society as a whole and contribute to better health and quality of life for the individuals concerned.