The Peer Education Project to improve mental health literacy in secondary school students in England: a qualitative realist evaluation

Worsening of adolescent mental health and exacerbated health inequalities after the COVID-19 pandemic calls for universal preventative strategies. The Mental Health Foundation's school-based Peer Education Project seeks to improve students' mental health literacy through peer educators (aged 14-18 years) teaching peer learners (aged 11-13 years) to recognise good and bad mental health, identify risk and protective factors, and seek help accordingly. Although previous before and after quantitative assessments have found the intervention to be effective, this realist evaluation aimed to qualitatively develop the theory of change, exploring how the mechanisms played out in different contexts to achieve the desired outcomes.Our initial programme theory was developed following expert stakeholder consultation and reviewing the literature. We divided mechanisms into resources and reasoning to explain how the intervention components (ie, resources), experienced within specific contexts, engendered responses in the participants (ie, reasoning), to produce observable outcomes. Data collected from six purposively recruited schools in England comprised staff interviews (n=11), student focus groups (n=15), and observations (n=5). Deductive and inductive analysis was undertaken, using NVivo-informed multiple causal statements represented as context-mechanism-outcome configurations (CMOcs), to test and refine the programme theory.We created several distinct CMOcs. For example, in learners accustomed to didactic teaching methods (context), conversing with educators having similar life experience (mechanism resource) endorsed and destigmatised help-seeking behaviour (mechanism reasoning) and facilitated a realisation that seeking help was appropriate and acceptable (outcome). Other mechanisms included the following: learners perceiving the information as tailored and relevant, educators feeling empowered, and a cultural shift percolating across the school.Our findings show how peer education can work to improve mental health literacy, which will inform changes to the intervention to maximise its effectiveness in different operational contexts. Future research could test our theory of change in a randomised controlled trial, and examine impacts on inequalities in a more diverse sample.National Institute for Health and Care Research School for Public Health Research.