Promoting healthy families: a three‐arm randomized controlled trial of Triple P and Circle of Security–Parenting versus treatment‐as‐usual for families with young children (2–6 years)

BACKGROUND: Parenting programs grounded in social learning (SL) and attachment theory are widely implemented, yet few trials have directly compared their effects across multiple parenting domains in community contexts. This study examined the relative effectiveness of an SL-based program (Triple P - Level 4 Group) and an attachment-based program (Circle of Security - Parenting, COS-P) against treatment-as-usual (TAU) when delivered online through community agencies. METHODS: A three-arm randomized controlled trial was conducted across four community organizations in Ontario, Canada. Caregivers of children aged 2-6 years (N = 502) were randomized (1:1:1) to Triple P, COS-P, or TAU. Primary outcomes were child behavioral difficulties (SDQ-Total) and parental overreactivity with post-intervention, 6-, and 12-month follow-up. Secondary outcomes included parental attributions, parenting stress, and caregiver mental health. Analyses followed an intention-to-treat framework using mixed-effects models (ClinicalTrials.gov #NCT04702191). RESULTS: Relative to TAU, Triple P demonstrated significant short-term reductions in emotional symptoms and conduct problems, and immediate improvements in hostile and helpless parenting and anxiety; however, most between-group effects did not persist beyond post-intervention. Effects on total child behavior problems at 12 months were no longer significant after correction for multiple testing. Improvements in parental attributions were sustained at 12 months. COS-P differed from TAU on only one outcome, at one time point. Within-group improvements in child behavior, dysfunctional parenting, and caregiver mood were observed in TAU, with COS-P and Triple P showing similar trends. Exploratory analyses suggested broader benefits for Triple P relative to COS-P. CONCLUSIONS: Triple P demonstrated selective short-term benefits relative to TAU across child behavioral and parenting outcomes, with sustained effects limited to parental attributions. COS-P showed no measurable effects relative to TAU. These findings highlight the importance of behavioral management and self-regulation components and point to the need for further research examining contextual moderators, maintenance strategies, and sustainable delivery approaches, including digital formats.