Evidence and Gap Map of Whole-School Interventions Promoting Mental Health and Preventing Risk Behaviours in Adolescence: Programme Component Mapping Within the Health-Promoting Schools Framework: An evidence and gap map.

Adolescence is a vulnerable period for the onset of mental disorders and risk behaviours. Whole-school interventions hold vast potential in improving mental health and preventing risk behaviours in this developmentally-sensitive cohort. Modelled on the World Health Organisation's Health-Promoting Schools Framework, whole-school interventions aspire for change across eight domains: (i) school curriculum, (ii) school social-emotional environment, (iii) school physical environment, (iv) school governance and leadership, (v) school policies and resources, (vi) school and community partnerships, (vii) school health services and (viii) government policies and resources. Through embodying a systems-based approach and involving the key stakeholders in an adolescent's life, including their peers, parents and teachers, whole-school interventions are theoretically more likely than other forms of school-based approaches to improve adolescent mental health and prevent risk behaviours. However, vague operationalisation of what is to be implemented, how and by whom presents challenges for stakeholders in identifying concrete actions for the eight domains and thus in realising the potential of the Framework. Mapping how whole-school interventions operationalise the eight domains enables appraisal of current practice against the recommendations of the Health-Promoting Schools Framework. This facilitates identification of critical evidence gaps in need of research, with the aim of fostering optimal translation of the Framework into practice to promote mental health and prevent risk behaviours in adolescence. Our EGM's objective was to map how randomised controlled trials of whole-school interventions promoting mental health and preventing risk behaviours in adolescence addressed the eight domains of a whole-school approach. Our EGM was conducted in accordance with a pre-registered protocol (PROSPERO ID: CRD42023491619). Eight scientific databases were searched: Ovid MEDLINE, Ovid Embase, Ovid PsycINFO, Ovid Emcare, CINAHL, ERIC, CENTRAL and Scopus. Expert-recommended sources of the grey literature were also searched, including the Blueprints for Healthy Youth Development registry of evidence-based positive youth development programmes and the SAMHSA Evidence-Based Practice Resource Centre. To be included in our EGM, studies had to involve randomised controlled trials or cluster randomised controlled trials comprising students aged 12 to 18. Interventions had to demonstrate a whole-school approach promoting mental health and/or preventing risk behaviours, including at least one program component addressing each of the curriculum-, ethos and environment-, and community-levels of a whole-school approach. Studies had to include an active or inactive comparator. Studies had to report on at least one of the mental health and/or risk behaviour outcomes detailed in the WHO-UNICEF Helping Adolescents Thrive Initiative, which includes positive mental health, mental disorders, mental health literacy, substance use, bullying and aggression. Two independent reviewers screened search results, with disagreements resolved by a third reviewer on the research team. Risk-of-bias assessments were completed by two independent reviewers for each included study using the Cochrane risk-of-bias tool, with disagreements resolved by a third reviewer on the research team. Data extraction for each included study was completed independently by two reviewers, in accordance with a prespecified template. Data extraction included study characteristics and intervention components, the latter of which was mapped against the eight domains of a whole-school approach. 12, 897 records were identified from the searches. A total of 28 studies reported in 58 publications fulfilled the inclusion criteria. The majority of interventions implemented by studies classified as either substance use prevention (10 of 28 studies) or multiple risk behaviour interventions (8 of 28 studies). The majority of studies involved students in lower secondary school grade levels, with only 5 of 28 studies targeting students in grades 10 to 12. The majority of studies were set in high-income countries, with minimal representation of low- and middle-income countries (5 of 28 studies). The interventions implemented by studies ranged from 9 weeks to 3 years in duration. Though 100% of studies involved students in the evaluation stage and 61% in the implementation of intervention strategies, only 39% involved students in the planning and 29% in the design of whole-school interventions. Significant variability existed in how frequently whole-school interventions addressed each of the eight domains, ranging from 7% to 100%. This included 100% of interventions implemented by studies addressing the school curriculum domain, 64% the school social-emotional environment domain, 46% the school physical environment domain, 50% the school governance and leadership domain, 61% the school policies and resources domain, 93% the school and community partnerships domain, 29% the school health services domain and 7% the government policies and resources domain. Despite different intervention foci, there was a clear overlap in whole-school intervention strategies within each domain. Our EGM identifies several critical foci for future research. These include the need to investigate (i) whether certain domains of a whole-school approach are critical to intervention success; (ii) whether addressing more domains translates to greater impact; and (iii) the relative effectiveness of common intervention strategies within each domain to enable the most effective to be prioritised. Our EGM identifies the need for greater investment in older adolescent populations and those from low- and middle-income countries. Finally, we encourage stakeholders including researchers, schools, public health and policy makers to consider four crucial factors in the design and planning of whole-school interventions and to investigate their potential impact on intervention success. These include: (i) the provision of training and support mechanisms for those implementing interventions; (ii) the decision between single-issue versus multiple-issue prevention programs; (iii) the optimal intervention duration; and (iv) the involvement of adolescents in the design and planning of whole-school interventions to ensure that interventions reflect their real-world needs, preferences and interests.