Background: Adolescent mental health problems have increased in prevalence. Teachers' Mental Health Literacy (MHL) may play an important role in public mental health prevention approaches. This systematic review and narrative synthesis aimed to identify what is known globally about the extent of secondary school teachers' MHL and the types and effectiveness of MHL interventions for secondary school teachers.
Methods: PsycINFO, PubMed, ERIC, EBSCO-Psychological and behavioural sciences collection, Web of Science, and Google Scholar were searched to identify studies until 29/04/2024. Two independent reviewers screened the returns.
Results: Twenty eligible studies were reviewed. Most intervention studies were from high-income countries and used a psycho-educative approach. Pre-intervention, teachers' levels of MHL were mixed across MHL domains. Post-intervention, increases in mental health knowledge and attitudes and decreases in mental health stigma were reported. Low use of standardised MHL measures, lack of randomised controlled trials, and lack of follow-up data affect evidence quality.
Conclusion: Interventions to improve secondary school teachers' MHL can be effective, at least in the short term. Evidence quality needs to be improved to inform recommendations on whether they should be part of a public mental health approach for adolescents.