The project will be implemented as a group project, with the City of Helsinki as the main implementer, and Centre of expertise on social welfare Socca/HUS, Osallisuuden Aika, Western Uusimaa Wellbeing Services County (under a letter of intent), Vantaa and Kerava Wellbeing Services County (under a letter of intent), Central Uusimaa Wellbeing Services County (under a letter of intent), Eastern Uusimaa Wellbeing Services County (under a letter of intent), and HUS Adolescent Psychiatry (under a letter of intent) as co-implementers. The main goal of the project is to bring about a lasting improvement in the integrated client and patient work between child welfare personnel in the City of Helsinki and Uusimaa wellbeing areas and HUS adolescent psychiatry personnel. This change will improve the timeliness of services for joint clients and more efficiently allocate the resources available across sectors to meet the support and care needs of joint clients and their families. As a result of the development work carried out within the project, the support and care needs of joint clients of child welfare and adolescent psychiatry can be addressed in a cost-effective manner. This is achieved by implementing the integration of child welfare and psychiatry more effectively through the collaboratively developed, client-centered operational models and solutions. The development work focuses on the participation of the child. The co-development process seeks to answer the question: What kind of ways of interacting and cooperating among multiple actors should be implemented in order the operational models to provide more benefit to clients compared to the current situation, and to improve the client’s experience of managing daily life and agency? The sub-objectives of the project include developing an operational model for network co-operation that is child-centered and research-based, with core elements unified, suitable for joint client cases of child protection and youth psychiatry in the City of Helsinki and Uusimaa wellbeing areas. Another sub-objective is to develop and pilot an integrated rehabilitation service for joint clients in need of intensive institutional care. The project innovatively, concretely, and comprehensively reforms the coordination of services and client-centered integration. A social innovation is created within the project by co-developing a new operational model between joint clients, child welfare professionals, and psychiatry professionals, improving the joint clients' experience of being supported and heard. Child participation is implemented in all phases of the project, from the planning of development activities to the experimentation of social innovations, and to the project’s evaluation and monitoring. The change aimed at in the collaboration practices between child welfare and adolescent psychiatry professionals is reasonably expected to have significant positive effects on the ability of vulnerable joint clients in need of strong support to manage daily life and agency. With the implementation of the model, multi-agency cooperation in the Uusimaa region will shift from parallel functioning to client-centered and coordinated integration, where the situations of children and their families are addressed holistically by professionals working together, rather than addressing individual problems within the services. Clients' ability to manage and act will be strengthened, and their well-being will increase as complex situations become clearer not only for clients but also for professionals through co-operation. This will, in turn, reduce the need for repeated inpatient care periods in HUS adolescent psychiatry as well as child welfare placements. Child welfare and adolescent psychiatric services will form a cohesive whole in the lives of young people, instead of being fragmented, reactive, and symptom-based. Demand for reactive services will decrease, and the connection of young people and their families to the support and care provided will be strengthened. This will result in significant cost savings.