A cluster-randomized trial of a classroom-based narrative intervention for adolescent peer support

Adolescents’ peer relationships are central to their flourishing, yet empirically validated, developmentally attuned interventions to support these relationships at school remain limited. This study evaluates Humans of Our Classroom , a classroom-based narrative intervention designed to strengthen adolescents’ peer connectedness through structured storytelling and reciprocal listening. Implemented in 46 classrooms across secondary schools in Spain and the United Kingdom, the intervention was evaluated using a cluster-randomized controlled trial with pre- and post-intervention surveys ( N = 609). Intention-to-treat analyses showed a trend-level increase in Student Personal Support (β = 0.11, 95% CI: -0.01, 0.22, p = .067). Among classrooms that completed the full intervention, a per-protocol analysis found a statistically significant increase in Student Personal Support (β = 0.13, 95% CI: 0.01, 0.25, p = .032); because per-protocol analyses do not preserve randomization, this finding should be interpreted as associational rather than causal. Further, exploratory subgroup analyses suggested larger associations for students with low social connectedness (e.g., high loneliness [β = 0.26, p = .008], low classmate support [β = 0.16, p = .050], low prosocial behavior [β = 0.18, p = .026]), low well-being (e.g., low meaning and purpose [β = 0.15, p = .048], or low flourishing [β = 0.21, p = .023]) at baseline, highlighting the intervention’s potential as a targeted protective factor for students with low social connection or wellbeing.