Background. Mental health in Chilean children and families is an urgent public health problem. Several epidemiological studies have shown that a significant percentage of the adult population has psychiatric disorders. For example, one recent study showed that 31.5% of the population aged 15 and over has some type of psychiatric pathology in their lives, and that 22.2% suffered from a mental disorder during the last year (Vicente et al., 2006). Today we know that many of the disorders present in the adult population begin in childhood and adolescence and that preventing their onset can have a significant impact on the future functioning of the individual. The few epidemiological studies on the Chilean child and adolescent populations show that the prevalence of psychiatric disorders among children between 4 and 11 years old is 27.8%, a higher percentage than was found in adolescents between 12 and 18 years old, which is 16.5% (Vicente et al., 2012). The most frequent disorders in the population between 4 and 11 years old were disruptive disorders (20.6%), followed by anxiety disorders (9.2%) (Vicente et al., 2012). Mental health problems generate a high burden of disease on society in general (Patel, et al., 2016); and there is an important gap in the treatment of these, especially in populations that are more economically vulnerable (Patel, et al., 2016). Prevention strategies appear to be the more recommendable options, mainly if these interventions can be implemented early and at low cost. Few preventive interventions, or interventions that increase resilience in the face of adversity, have been rigorously evaluated in Chile. There is substantial evidence that shows that strengthening social and emotional learning skills can reduce the incidence of mental pathology and improve various academic indicators (Domitrovich et al., 2017). These social-emotional skills include the ability to identify and express emotions, to be able to adapt to social context, to regulate emotions, the ability to inhibit behaviour, and problem-solving skills (Denham, 2006; Domitrovich et al., 2017). Deficits in these skills have been associated with the appearance of both internalization problems (emotional problems such as depression and anxiety) and externalization problems (such as disruptive behavioural problems), as well as peer rejection (Garner \& Waajid, 2012).

The curriculum of the Interpersonal Cognitive Problem Solving Program, also known as I Can Problem Solve (ICPS) (Shure, 1992), is focused on the development of the cognitive process and children's social problem-solving skills. That is, it is a program that explicitly promotes cognitive regulation (skills for listening and paying attention, sequencing and planning tasks) and solving social problems (thinking up alternative solutions, causal thinking, means-to-an-end thinking, and sequential planning). But it also includes the promotion and learning of emotional processes (particularly emotional expression/knowledge, perspective, and empathy) (Jones et al., 2017). Several studies conducted among disadvantaged population have shown that students who received ICPS had better results regarding increasing pro-social behaviours and reducing aggressive behaviour compared with students in the control group (Shure \& Spivack, 1982; Boyle \& Hassett-Walker, 2008). ICPS is a universal intervention designed to promote interpersonal cognitive processes and problem-solving skills in children from preschool through 6th grade. This project will adapt the preschool program, which has a total of 59 sessions. Each session lasts around 20 minutes, and the trained facilitator follows a simple manual that guides their work with the students on ICPS vocabulary and concepts and the development of problem-solving skills such as practising alternative solutions, consequences and the sequential thought (solutions-consequences). An interactive technique and guided discussion strategies are used to solve problems. Interactive methods include games, role-playing, and the use of stories, illustrations and puppets. These contents may also be used in other curricular activities for children, whether they are working on Math, Reading or Science. Children learn how to think and not what to think.

Aims. The general objective of this study is the evaluation of the acceptability and feasibility of an adapted version of ICPS in the national context at educational institutions with high socio-economic vulnerability, with the ultimate goal is of increasing social-emotional competence and reducing emotional and behavioural problems in preschoolers.

Methods. A pilot study consisting of two phases. Firstly, a formative stage when all intervention evaluation materials will be prepared, including the validation of instruments assessing socio-emotional skills; and curriculum of ICPS Preschool Program will be translated, edited and adapted, working closely with the author of the program Dr Myrna Shure. Secondly, the program will be implemented using a three-arm randomised controlled trial design. The acceptability and feasibility of its implementation in the national context will be evaluated, and changes in the development of social-emotional skills, behavioural problems and mental health, before and after the intervention. There will be two Intervention groups: 1) Schools implementing the ICPS program delivered by the school early teacher, trained by the research team; and 2) Schools implementing the ICPS program delivered by an early teacher hired and trained by the research team, who will work collaboratively with the school early teacher. A control group will consist of school implementing their usual teaching activities.