Mental health problems represent one of the leading drivers of overall disease burden. Half of all lifetime psychiatric disorders present before adulthood, with a point prevalence of between 10% and 20% of children and adolescents experiencing mental health difficulties. In addition, more than 40 percent of youths with a lifetime psychiatric disorder go on to develop at least one additional mental illness concurrently or later in life. This adds significant complexity to diagnosis and interventions and further increases the likelihood of negative outcomes, such as criminality, low educational attainment and unemployment. A developmental perspective that investigates the interrelations between multiple mental health issues from early life up until adulthood is likely to offer important insights into why mental health problems commonly co-occur and can consequently inform prevention strategies. In the current project, using state-of-the art statistical techniques, we propose to analyse the developmental relations of mental health problems. We will further examine potential factors linking mental health problems together such as genetic predispositions to mental health problems, perinatal risk factors, and school problems. The results of this project will have important clinical implications. In particular, they will shed light on potential risk factors that drive the development of co-occurring mental health problems, give insights into which symptoms are likely to precede other symptoms and further help identify other factors that might exacerbate the development of co-occurring mental health problems. Thus, findings will inform early intervention strategies for preventing the development of secondary mental health disorders.