Despite widespread concern about the impact of COVID-19 on adolescent mental health, there remains limited empirical evidence that can causally attribute changes to the pandemic. The current study aimed to overcome existing methodological limitations by exploiting a serendipitously occurring natural experiment within two ongoing, multi-phase cluster randomized controlled trials. Depressive symptoms (primary outcome), externalizing difficulties and life satisfaction (secondary outcomes) were assessed at baseline (phase 1 [pre-COVID-19 group]: September – October 2018, phase 2 [COVID-19 group]: September – October 2019) and 1-year follow-up (pre-COVID-19 group: January – March 2020, COVID-19 group: February – April 2021). Participants in phase 1 ( N = 6419) acted as controls. In phase 2, participants ( N = 5031) were exposed to the COVID-19 pandemic between the baseline and follow-up assessments providing a natural experimental design. The primary analysis used a random intercept linear multivariable regression model with phase (exposure to the COVID-19 pandemic) included as the key predictor while controlling for baseline scores and individual and school-level covariates. Depressive symptoms were higher and life satisfaction scores lower in the group exposed to the COVID-19 pandemic. Had the COVID-19 pandemic not occurred, we estimate that there would be 6% fewer adolescents with high depressive symptoms. No effect of exposure to the pandemic on externalizing difficulties was found. Exploratory analyses to examine subgroup differences in impacts suggest that the negative impact of the COVID-19 pandemic on adolescent mental health may have been greater for females than males. Given the widespread concern over rising adolescent mental health difficulties prior to the pandemic, this paper quantifies the additional impacts of the pandemic. A properly resourced, multi-level, multi-sector public health approach for improving adolescent mental health is necessary. Following in-principle acceptance, the approved Stage 1 version of this manuscript was preregistered on the OSF at https://doi.org/10.17605/OSF.IO/B25DH . This preregistration was performed prior to data analysis.

BackgroundThere are increasing rates of internalising difficulties, particularly anxiety and depression, being reported in children and young people in England. School-based, universal prevention programmes are thought to be one way of helping tackle such difficulties. This protocol describes a four-arm cluster randomised controlled trial, investigating the effectiveness of three different interventions when compared to usual provision, in English primary and secondary pupils. The primary outcome for Mindfulness and Relaxation interventions is a measure of internalising difficulties, while Strategies for Safety and Wellbeing will be examined in relation to intended help-seeking. In addition to the effectiveness analysis, a process and implementation evaluation and a cost-effectiveness evaluation will be undertaken.Methods and analysisOverall, 160 primary schools and 64 secondary schools will be recruited across England. This corresponds to 17,600 participants. Measures will be collected online at baseline, 3–6 months later, and 9–12 months after the commencement of the intervention. An economic evaluation will assess the cost-effectiveness of the interventions. Moreover, a process and implementation evaluation (including a qualitative research component) will explore several aspects of implementation (fidelity, quality, dosage, reach, participant responsiveness, adaptations), social validity (acceptability, appropriateness and feasibility), and their moderating effects on the outcomes of interest, and perceived impact.DiscussionThis trial aims to address important questions about whether schools’ practices around the promotion of mental wellbeing and the prevention of mental health problems can: (1) be formalised into feasible and effective models of school-based support and (2) whether these practices and their effects can be sustained over time. Given the focus of these interventions on mirroring popular practice in schools and on prioritising approaches that present low-burden, high-acceptability to schools, if proved effective, and cost-effective, the findings will indicate models that are not only empirically tested but also offer high potential for widespread use and, therefore, potentially widespread benefits beyond the life of the trial.Trial registrationISRCTN16386254. Registered on 30 August 2018.

Evidence for the association between mental health difficulties and academic outcomes is sparse and shows mixed results. The aim of this study was to investigate the association between educational attainment, absenteeism and mental health difficulties while controlling for various child characteristics such as special education needs and socioeconomic background. 15,301 year 7 pupils (mean age: 11.91; SD = 0.28) from England completed the Strengths and Difficulties Questionnaire. Attainment, persistent absenteeism and child characteristics were derived from the national pupil database. Multilevel regression analysis showed that mental health difficulties were negatively associated with attainment and positively associated with persistent absenteeism. When all mental health difficulties were modelled simultaneously, behavioural difficulties, hyperactivity/attention difficulties and difficulties with peers were negatively associated with attainment. Emotional difficulties and hyperactivity/attention difficulties were positively associated with persistent absenteeism. The results of the current study highlight the importance of integration between mental health support and policy creation in relation to mental health difficulties and wellbeing in schools.

The substantial time that children and young people spend in schools makes them important sites to trial and embed prevention and early intervention programmes. However, schools are complex settings, and it can be difficult to maintain school engagement in research trials; many projects experience high levels of attrition. This commentary presents learning from two large-scale, mixed-methods mental health intervention trials in English schools. The paper explores the barriers and challenges to engaging schools in promotion or early intervention research and offers detailed recommendations for other researchers.

IntroductionThe prevalence of emotional difficulties in young people is increasing. This upward trend is largely accounted for by escalating symptoms of anxiety and depression. As part of a public health response, there is increasing emphasis on universal prevention programmes delivered in school settings. This protocol describes a three-arm, parallel group cluster randomised controlled trial, investigating the effectiveness and cost-effectiveness of two interventions, alongside a process and implementation evaluation, to improve mental health and well-being of Year 9 pupils in English secondary schools.MethodA three-arm, parallel group cluster randomised controlled trial comparing two different interventions, the Youth Aware of Mental Health (YAM) or the Mental Health and High School Curriculum Guide (The Guide), to Usual Provision. Overall, 144 secondary schools in England will be recruited, involving 8600 Year 9 pupils. The primary outcome for YAM is depressive symptoms, and for The Guide it is intended help-seeking. These will be measured at baseline, 3–6 months and 9–12 months after the intervention commenced. Secondary outcomes measured concurrently include changes to: positive well-being, behavioural difficulties, support from school staff, stigma-related knowledge, attitudes and behaviours, and mental health first aid. An economic evaluation will assess the cost-effectiveness of the interventions, and a process and implementation evaluation (including a qualitative research component) will explore several aspects of implementation (fidelity, quality, dosage, reach, participant responsiveness, adaptations), social validity (acceptability, feasibility, utility), and their moderating effects on the outcomes of interest, and perceived impact.Ethics and disseminationThis trial has been approved by the University College London Research Ethics Committee. Findings will be published in a report to the Department for Education, in peer-reviewed journals and at conferences.Trial registration numberISRCTN17631228.ProtocolV1 3 January 2019. Substantial changes to the protocol will be communicated to the trials manager to relevant parties (eg, ISRCTN).