The PLUSS (Mental health, learning, development, collaboration around preschool children) is a collaborative project involving guardians, Jönköping County´s health care, preschools and social services. The project studies the implementation of a "One way in"-model that provides coordinated services to screen, evaluate and treat toddlers with behavioral problems. The project also provides parental interventions and education for preschool teachers.

The study aims to investigate a) implementation of the PLUSS model, b) effectiveness of the model and the included parental training program on behavioral problem and their longitudinal development among preschool children, c) parental wellbeing and satisfaction. In the long term, the goal is to reduce mental health problems among children, adolescents and their families and to provide support for a functioning everyday life.

The Jönköping Health Care managers for Child Health Care, Habilitation Center, Child and Adolescent Psychiatry and Rehabilitation Center (Speech Therapist) searched at 2018 government funding during this collaborative PLUSS-project. They have since money was awarded to the project in 2019, been formatted as a steering group for these clinical research project. An operational interprofessional working group appointed by the managers to conduct clinical and research work under the guidance of a disputed project manager of 40%. Information about the PLUSS-project and collaboration with the municipalities' activities (preschool and social services) started in 2019.

Ethics approval has been granted by the National Ethics Board (#2019-04839). Informed consent is obtained from all actors: both parents, managers, preschool educators, CHP and CHN. All data is registered with fp-number and is encoded directly at the time of collection considering the protection of privacy. Code template for translation between fp-no and the test subject can be found in a logbook that is kept inaccessible to unauthorized persons. The results are reported only at the group level, where no personal data will be recognizable. All data processing takes place following Swedish data law. The parents have been informed that they receive the same care whether they participate in the study or not. The project could cause concern for the parents as they answer the questionnaire and become aware of the child's possible problem. Here it is an advantage that the CHP uses the questionnaire in the assessment interview so that the parent has the opportunity to ask questions or talk about his child's needs and strengths. Recruitment of the control group is done through the county parts that have not yet been included in the clinical trial of new methods. This means that children/families are not withheld from treatment they would otherwise receive.

After the assessment interview and with the parents' consent, the Child Health psychologist contacts the child's preschool. The preschool manager and preschool teacher may consent to participate in the study and the preschool teacher answers questionnaires. The behavior of the children in the preschool will be paid extra attention to the teachers as they are asked to assess the behavior of the individual child. This could lead to children's problem behavior being highlighted in a way that can change how teacher's behaved towards individual children. However, an exaggerated emphasis on the negative is counteracted by the teacher being also asked to estimate the child's mental health in the form of commitment and social interaction. The project focuses on efforts in the child's environment that are helpful to all children, not just those with special needs.

Inclusion Criteria:

• Development Delay
• Interaction, contact difficulties
• Language and communication difficulties
• Difficulties in everyday function
• Motor difficulties
• Concentration / hyperactive
• Self-regulation
• Acting / boundaries
• Anxiety
• No claim to diagnosis

Exclusion Criteria:

• Not only support in the parent role, without any of the problems above.

We are not supposed to share the data of the ethical considerations.

Children who are referred to a Child Health psychologist at the age of 1.5-4 (mostly after 2.5 years of supervision at the Child Health Nurse).

Informants are parents, preschool teachers, child health care psychologists and nurses.