RESUMO
Early adolescence is a key developmental phase for promoting positive mental health and preventing psychological difficulties. Despite calls to develop the evidence base for universal interventions in early adolescence and the promise of process-based CBT, the literature is devoid of empirical investigations of the efficacy of universal process-based CBT in this cohort. This cluster randomized controlled trial aimed to extend the empirical literature by evaluating the efficacy of a six-session universal process-based CBT intervention in elementary schools. Twenty-nine schools were randomly allocated to intervention or waiting list control groups. Six hundred four participants completed measures of positive mental health, resilience, emotional literacy, and mindfulness at baseline, post-intervention, and six-week follow-up. Although participants reported that the intervention was satisfactory, it did not yield significantly superior growth rates on the outcome measures than the control condition at post-intervention or follow-up. Implications of the findings and directions for future research are discussed.