Interventions to reduce loneliness in children and adolescents (4–18 years): A systematic review and meta-analysis with narrative synthesis of study-level characteristics

Loneliness in youth is linked to poor mental and physical health, yet the effectiveness of interventions remains unclear. Given its distinct developmental presentation, this meta-analysis synthesises interventions targeting loneliness in individuals aged 4–18 to inform age-appropriate strategies. It examines the effects of interventions on loneliness and includes a narrative synthesis of intervention and sample characteristics. We conducted a systematic literature review and meta-analysis of quantitative studies up to March 2024, focusing on interventions where loneliness was the primary target in school-aged youth. Nineteen studies were included in the SLR, of which 18 were included in the meta-analysis (6 RCTs, 6 multi-cohort, and 6 single-cohort studies). RCTs showed a small, non-significant reduction in loneliness (Hedges' g = −0.20, 95% CI [−0.42, 0.02], p = .07), with social and emotional skills training interventions being most effective. Multi-cohort studies showed a negligible effect (Hedges' g = −0.01, 95% CI [−0.08, 0.07], p = .84). Single-cohort studies indicated a moderate, non-significant effect (Hedges' g = −0.55, 95% CI [−1.29, 0.18], p = .14). Interventions targeting loneliness show promise in reducing loneliness, particularly when they incorporate social and emotional learning. Future research should integrate qualitative approaches and consider loneliness within broader mental health and well-being frameworks to support the development of more comprehensive, youth-centred interventions. • Loneliness is a growing critical concern among youth • First meta-analysis on loneliness-specific interventions in school-aged youth • Social–emotional skills training shows most promise for reducing loneliness • Narrative synthesis supports improvements across broader mental health and wellbeing • Calls for more high-quality, youth-specific intervention research