Preventing Gambling Among Adolescents: An Umbrella Review of School-Based Prevention Programmes

In recent years, both land-based and online gambling have become increasingly normalised and socially accepted activities. Despite legal restrictions aimed at preventing underage access, evidence confirms concerning prevalence rates among adolescents. Over the past three decades, preventive programmes have been developed to reduce the incidence of problem gambling, alongside several systematic reviews. This umbrella review synthesises and critically contrasts the findings of previous reviews. A systematic search was conducted across seven databases (ProQuest, PubMed/MEDLINE, Scopus, Web of Science, PsycINFO, ScienceDirect, CENTRAL) and the ClinicalTrials.gov registry in line with PRISMA 2020 guidelines. Reviews evaluating adolescent gambling prevention using behavioural, severity, knowledge, risk-perception or attitude outcomes were eligible. Methodological quality and overlap were assessed using AMSTAR-2 and CCA. Seven systematic reviews and meta-analyses were identified, comprising 38 primary-study entries in the overlap matrix. These entries generated 107 review-study inclusions (CCA = 30.26%), indicating substantial overlap across reviews. Interventions consistently improved knowledge and beliefs, but behavioural effects were modest, inconsistent, and rarely sustained. The seven reviews draw heavily on a limited and overlapping body of primary studies. Cognitive improvements were reported, but all seven reviews were rated critically low by AMSTAR-2 and comparative evidence for multicomponent and skills-based programmes remains limited. More rigorous designs, longer follow-ups, and consistent outcome measures are required.