Promoting self-regulation and cooperation in pre-kindergarten children with conduct problems: a randomized controlled trial.

OBJECTIVE: To evaluate the effectiveness and mechanisms of Hitkashrut, a "common elements" co-parent training (PT) program for early intervention with preschoolers (3-5 years of age) at risk for conduct problems (CP).

METHOD: A randomized controlled trial with 140 participants in PT and 69 in a minimal intervention control group. The primary outcome (presence of CP) was assessed at pre-intervention, post-intervention, and 1-year follow-up. Callous-unemotional traits, effortful control, parental distress, negative/inconsistent parenting, and couple relationship quality were assessed at pre- and post-intervention, whereas callous-unemotional traits and effortful control were also assessed in the PT group at follow-up. Retention was 87.1% at post-intervention and 60% at follow-up. Hitkashrut incorporated evidence-based components of established PT programs into a culturally adapted protocol. The facilitators were trained and supervised psychologists working in Israel's Educational Psychology Services.

RESULTS: Intervention effect (Cohen's d) was large at post-intervention (ES = .76, p < .001), and an additional medium effect was found at follow-up (ES = 0.63, p < .001). Parallel post-intervention and follow-up intervention effects were also found in the degree of clinically significant improvements. Effects of the intervention on callous-unemotional traits (ES = 0.85, p < .001) and effortful control (ES = 0.47, p < .001) were maintained at follow-up. Follow-up improvement in CP was mediated by improvements in parental practices and distress.

CONCLUSIONS: Hitkashrut's implementation and subsequent dissemination in real-world settings demonstrates the potential effectiveness of common elements programs to promote innovations within service-delivery systems. Improvements in dispositional variables and the mediated follow-up effect support theoretical cascade models that emphasize early developmental malleability and the growing preventive effects of PT's facilitated parental changes on disruptive developmental trajectories. Clinical trial registration information - The effect of a "common elements" co-parent training program (called 'Hitkashrut') on conduct in preschoolers at risk for conduct problems; https://www.anzctr.org.au; ACTRN12612000148875.