Effectiveness of a universal school-based intervention for reducing internalising problems in Irish primary school: a cluster randomised control trial

There is a need to promote positive mental health in youth due to the increasing prevalence of mental health difficulties in childhood and adolescence. Schools are well placed to support the development of emotional wellbeing and resilience in young people, and to provide early intervention for psychological difficulties. The research presented in this thesis explored the impact and implementation of school-based mental health and wellbeing programmes. Firstly, this thesis aimed to explore the current state of the literature in relation to the associations between level of implementation in school-based programmes and intervention outcomes. A narrative synthesis of 26 studies revealed that implementation is important for intervention effects, and identified that participant responsiveness and intervention dosage were the implementation components most often linked to programme outcomes. Secondly, this thesis aimed to examine the effectiveness of a novel, universal school-based programme, the A Lust for Life (ALFL) Schools Programme, for the outcomes of internalising problems, coping strategies and self-efficacy, using a cluster randomised control trial. Four hundred and seventy pupils completed measures at three timepoints (baseline, post-intervention and 6- week follow-up). Findings from the empirical study revealed that the intervention did not have an effect on the outcome variables. The overall findings from this thesis suggest that programme implementation and delivery have an impact on intervention effects, and should be considered when interpreting outcomes. Collectively, the two studies contribute to the evidence base for school-based programmes and provide a number of implications for practice.