Mental disorders have a large burden of disease and are the main contributor to chronic conditions for the population of Europe. They are associated with high costs and there is an existing scarcity in resources due to increasing costs and limited budget. For policymakers, it is important to have knowledge about the economic consequences and benefits of treatments for these disorders. The overall aim of my thesis is to investigate the cost-utility of collaboration models for mental disorders from a societal perspective. The first part of this thesis concerns the allocation of patients and the development of an evidence based decision tool. In the second and third part of this thesis cost-utility is determined for interventions that have their emphasis on collaboration. The second part contains interventions that have integrated collaboration between settings. More specifically, in these chapters the cost-utility is determined for collaborative care models provided in different settings for two common mental disorders; Major depressive disorder (MDD)-and generalized anxiety disorder (GAD) /panic disorders (PD). The third part of this thesis reflects upon interventions that are based on collaboration. In this part, an overview is provided of economic evaluations for family interventions. Additionally, a cost-utility study is conducted for a specific family intervention (Multidimensional Family Therapy (MDFT)), which is provided to adolescents with a substance use disorder, externalizing disorder or delinquency.