Evaluating the efficacy and cost-effectiveness of the school-based Solution-focused Intervention for Mental health (SIM) in first year of upper secondary school students

Research problem and specific questionsThere is a lack of evidence-based school interventions to promote mental well-being among students in Swedish upper secondary schools.

Therefore, in 2018 the development of the Solution-focused Intervention for Mental health (SIM) for upper secondary school students began.

Preliminary results from a feasibility study during 2021 show a statistically significant increase in mental well-being after the intervention.

With the following questions, the aim is now to continue the evaluation:Does SIM promote mental well-being and if so by how much?Does SIM prevent mental health problems and if so by how much?Is SIM cost-effective compared to usual school provision and student health?To what extent do SIM sessions follow the manual-based solution-focused coaching process and its techniques?Data and methodTo answer questions 1-3, a two-armed randomized controlled trial (RCT) with an intervention group that receives SIM and a control group with the usual school provision, is conducted.

Randomization is done by class (n=28, ICC=0.06, VIF=2.7), since the intervention takes place in mentor groups.

Based on preliminary results, paired measurements of 559 subjects are required to detect with 80% power a small effect (d=0.196) at a significance level of 0.05.

The evaluation is based on validated measurement instruments before and after the intervention and after 6 and 12 months. To answer question 4, an observational study is carried out on a sample of mentor groups from the RCT. An assessment protocol is used that was previously developed and tested in another feasibility study.

Societal relevance and utilisation Growing evidence shows that high levels of mental well-being independently predict less subsequent mental illness and have a range of positive effects on individuals and society.

This project will contribute to new knowledge in the field by evaluating a new universal intervention for the school to use in its promotional work.Plan for project realisationThe project is carried out in close collaboration with targeted practices within two regions and two Swedish municipalities.

It is led by a regional research leader in public health together with a research group with both national and international representation.

The costs are motivated by salaries for researchers and a doctoral students, as well as operating costs for an intervention that in close collaration with participating schools will reach many students.