Background: Depressive disorders are experienced by 3-5% of the adolescent population at any point of time. They adversely affect adolescent development in a range of areas and greatly increase risk for suicide. The present study investigated the effectiveness of a universal intervention designed to reduce depressive symptoms among students commencing high school.
Methods: Twenty-five pairs of secondary schools matched on socio-economic status were randomly assigned to either an intervention or a comparison group (n = 5,634 Year 8 students). The intervention extended over a 3-year period and utilised a comprehensive classroom curriculum programme, enhancements to the school climate, improvements in care pathways, and community forums. A range of measures completed by students, average age at baseline = 13.1 years (SD = .5), and teachers was used to assess changes in depressive symptoms, risk and protective factors relevant to depression, and the quality of the school environment.
Results: Changes in the level of depressive symptoms and in the levels of risk and protective factors experienced by students in the two groups did not differ significantly over the 3 years of the study. Furthermore, statistically significant differences in the ratings of school climate across this time period were found only for staff-rated assessments.
Conclusions: Despite using an extensive, structured programme, based on best evidence to increase protective factors and reduce risk factors at the individual and school levels, the intervention did not reduce levels of depressive symptoms among participating adolescents. The results draw attention to the difficulties faced when implementing large-scale, school-based, universal preventive interventions. These include the need to develop methods to effectively train teachers across large geographical regions to deliver new interventions with fidelity, the difficulty of engaging young adolescents with prevention programmes, and the long period of time required to implement policy and practice changes at 'whole-school' levels.