A rapid realist review of universal interventions to promote inclusivity and acceptance of diverse sexual and gender identities in schools

Adolescent depression, anxiety and self-harm are common, rising, and major risk factors for suicide. Sexual and gender minority (SGM) young people face elevated risks due to stigma, prejudice and discrimination, as described by minority stress theory. In schools, SGM youth experience higher bullying, exclusion and marginalization than heterosexual or cisgender peers. Universal school-based interventions that promote inclusivity and acceptance of diverse sexual and gender identities could mitigate modifiable risk factors and help prevent mental health problems. However, evidence had not been synthesized regarding which universal interventions exist, for whom and in what contexts they work, and the mechanisms by which they operate. Using a rapid realist review approach, the study aimed to develop and refine programme theories using context–mechanism–outcome (CMO) configurations to explain how interventions might reduce depression, anxiety, self-harm and suicidality among SGM students.

Prior literature documents substantially higher rates of depression, anxiety, self-harm and suicidality among sexual minority youth, and increased mental health risk among gender minority youth, relative to heterosexual and cisgender peers. Studies show SGM students encounter greater bullying, discrimination and negative school climates, which are associated with poorer academic and mental health outcomes. Universal public health interventions have been effective in other domains but development for mental health prevention lags. Before this review, no synthesis had focused on universal, school-based interventions to promote inclusivity and acceptance of diverse sexual and gender identities, nor on the contexts and mechanisms underlying their effectiveness. Realist and rapid realist approaches have been used to generate programme theories across health and education, emphasizing the importance of CMO configurations and stakeholder input to understand not only if but how and for whom interventions work.

Design: Rapid realist review following RAMESES guidance to develop and refine programme theories using context–mechanism–outcome (CMO) configurations. A reference group comprising a Young Person’s Advisory Group (YPAG), a Stakeholder’s Advisory Group (SAG), and experts in SGM mental health research and practice informed scoping, theory development, interpretation, and dissemination. Protocol preregistered on PROSPERO (RecordID=279193). Search: Exploratory scoping in Google Scholar to develop initial programme theory; main database searches in PubMed, PsycINFO, and Web of Science on 14 September 2021. Search terms covered sexual and gender identities (e.g., LGBTQ+, lesbian, gay, bisexual, transgender, non-binary) and school-based interventions (e.g., policy, curriculum). Inclusion/exclusion: Any study design and relevant grey literature in English; universal interventions targeting all secondary school students (ages ~11–18) and/or staff; outcomes included depression, anxiety, self-harm, suicidality, and indicators of inclusivity/acceptance (bullying, climate, connectedness, stigma, discrimination). Selection and screening: Records imported into Rayyan; duplicates removed. Two reviewers screened titles/abstracts; 10% double-screened by a third reviewer. Full texts screened by five researchers with 10% double-screened; disagreements resolved by consensus or lead author. PRISMA: 5,155 records from databases and 16 from other sources; 3,898 screened after deduplication; 407 full texts assessed; 53 sources included. Data extraction: Standardized schedule captured study aims/design, intervention type, sample characteristics, contexts, mechanisms, outcomes, and CMOs. Data synthesis: Initial programme theory based on minority stress literature, scoping sources, and reference group input. CMOs grouped into five intervention themes and refined iteratively with stakeholder feedback to address contexts, mechanisms, outcomes, subgroups, and potential harms. Quality/rigour: Assessed credibility and trustworthiness of methods for contribution to theory development. Of 53 sources, 22 had trustworthy/credible methods; 19 somewhat or unclear; 12 did not fulfill either criterion. Evidence base: 52 peer-reviewed and one other source; designs included 14 qualitative, 6 mixed methods, and 25 quantitative (17 cross-sectional, 5 pre–post, 2 cohort, 1 RCT); 6 reviews; 65% conducted in North America; 13 reported mental health outcomes.

- Five universal intervention themes were identified: (1) Gay–straight alliances (GSAs) or similar student clubs; (2) Inclusive antibullying and harassment policies; (3) Inclusive curricula; (4) Workshops and media-based interventions; (5) LGBTQ+ ally and staff training. - Across themes, interventions tended to reduce bullying, discrimination and marginalization, improving school climate, safety, connectedness and, in some cases, mental health outcomes (e.g., lower self-harm and suicidality). - Contexts and mechanisms: • GSAs/clubs: Associated with reduced bullying/discrimination and improved safety, attendance and academic performance via normalization/validation, empowerment, improved relationships, and safe spaces; more effective when long-established, integrated into whole-school strategies, in positive climates, and when LGBTQ+ staff engage as role models. Potential harms include increased visibility leading to bullying in unsupportive climates. • Inclusive antibullying policies: When LGBTQ+ specific, supported by leadership, known and implemented by staff, and include education/support for bullies, these policies reduce homophobic aggression, increase safety and self-esteem, and reduce self-harm and suicidality. Effects may be weaker for bisexual and gender minority students and less persistent among boys. General (non-LGBTQ+ specific) policies do not reduce SGM bullying. Potential harms include backlash or false sense of safety in hostile environments. • Inclusive curricula: Positive representation and early implementation increase understanding and acceptance, validate SGM identities, reduce victimization and suicidal ideation, and improve well-being and school climate. Effective strategies include avoiding deficit narratives, highlighting role models, integrating LGBTQ+ topics across subjects (including sexual health), fostering reflection, and co-design with students/teachers. Potential harms include community backlash and insensitive delivery if teachers are undertrained. • Workshops/media interventions: Peer-led (SGM) workshops and student-led media can increase empathy and understanding, decrease bullying, and raise willingness to intervene. Effects may vary by gender and context; some evidence of backfire among male students in a Netherlands study. • Ally and staff training: Increases staff capacity to create safe spaces, support interventions, refer to services, and correctly use pronouns; associated with reduced victimization, improved safety, self-esteem, and mental health. Training should include how to discuss and intervene on homophobic language and bullying and be co-designed/delivered with SGM staff and students. - Subgroups and contexts: Interventions may be less effective for boys/young men, gender minority students, and bisexual students. Interventions generally work best in supportive school climates and when staff are trained. - Evidence base: 53 sources (1995–2021); 65% from North America; 13 reported mental health outcomes; only one RCT. PRISMA numbers: 5,155 database records plus 16 other; 53 included.

The review addressed which universal school-based interventions promote inclusivity and acceptance of diverse sexual and gender identities, and for whom, in what contexts, and why. Synthesized CMO-based programme theories indicate that GSAs/clubs, inclusive policies, inclusive curricula, workshops/media interventions, and ally/staff training can reduce bullying and discrimination, improve school climate and connectedness, and may reduce self-harm and suicidality among SGM students. School climate emerged as a central determinant of success, with interventions being complementary: policies and curricula can set supportive norms and structures, enabling successful implementation of GSAs/clubs and workshops. Representation matters; interventions are more impactful when led or supported by SGM role models and peer educators, and when teachers are trained and confident to intervene. Differential effects suggest adapting approaches for boys/young men by addressing masculinity and social status rather than labeling homophobia/biphobia/transphobia directly, and tailoring policies for bisexual and gender minority students. Sequencing may enhance impact: implement inclusive curricula and policies before launching GSAs to signal institutional support and minimize risk of backlash. Co-design and co-delivery with SGM students, staff, and lived-experience experts can increase relevance, acceptability and effectiveness. Overall, the findings support the initial theory that increasing inclusivity and acceptance can help prevent mental health problems among SGM youth, while highlighting mechanisms and contexts necessary for successful, safe implementation.

This rapid realist review synthesizes evidence on universal school-based interventions to promote inclusivity and acceptance of diverse sexual and gender identities and presents programme theories explaining how, for whom, in which contexts and why they can work. Five complementary approaches—GSAs/clubs, inclusive policies, inclusive curricula, workshops/media, and ally/staff training—can reduce bullying and discrimination, improve school climate and connectedness, and potentially reduce self-harm and suicidality among SGM students, especially when supported by trained staff and a positive school climate. Practical implications include implementing multiple, mutually reinforcing interventions; prioritizing early, positive, and representative inclusive curricula; establishing and enforcing LGBTQ+-specific policies; investing in comprehensive ally/staff training; involving SGM role models; and co-producing interventions with students and lived-experience experts. Future research should include randomized controlled trials and robust quasi-experimental studies, evaluate implementation and specific components to clarify CMOs, assess effects across SGM subgroups (including gender minority and bisexual youth) and demographic moderators (age, ethnicity, religion, disability), and measure a broader range of mental health outcomes (including depression and anxiety).

- Rapid realist approach did not aim for exhaustive capture of all studies; reliance on relevance to programme theory may introduce selection bias. - Limited generalizability: most studies from North America and Australia; sparse evidence from low- and middle-income countries. - Methodological limitations: only 22 of 53 sources had trustworthy and credible methods; only one randomized controlled trial; many cross-sectional studies. - Outcome limitations: few studies reported depression and anxiety; more data exist on self-harm and suicidality and school climate outcomes. - Heterogeneity and subgroup gaps: few studies large enough to assess differences across SGM subgroups; limited evidence on moderators such as age, ethnicity, religion, disability, and severity. - Context sensitivity: potential for harms (e.g., backlash, increased visibility leading to bullying) in unsupportive climates underscores need for careful implementation and sequencing.