Ethical approval
Completed questionnaires contained limited personal information to preserve anonymity. Gender and age were the only demographics collected from pupils. The trial received full ethical approval by Swansea University Ethical Committee on 29/10/2019 (Reference number: 2018–0272–259). Informed consent from participants was waived by the Swansea University Ethical Committee. This was on the basis that the intervention programme was being delivered as part of the National Curriculum and was being delivered within schools alongside other lessons within the learning curriculum. Parents were informed by each school that the Mental Health Literacy programme was being delivered as part of the curriculum and were given the opportunity to withdraw their child from these lessons if they wished.