Effects of Topper Training on psychosocial problems, self-esteem, and peer victimisation in Dutch children: A randomised trial.

Most interventions aimed at improving social interactions either target internalising or externalising problem behaviour in children. However, a recent review shows that a transdiagnostic approach might fit better to the diversity of problems within a group and within an individual (comorbidity). We examined the effectiveness of a transdiagnostic intervention, called Topper Training: a cognitive behavioural intervention in the peer group with parents included, that targets both internalising and externalising behaviour problems. A randomised trial with a waiting list control group was conducted, using 132 children with mild to severe psychosocial problems. Children were randomised into 77 intervention and 55 waiting list children (50% boys; age = 8-11 years). GLM repeated measures analyses yielded significant intervention effects directly after the training on parent-reported (but not teacher-reported) emotional symptoms (Cohen's d = .70), peer relationship problems (d = .41), and impact of these problems (d = .59). Significant effects were also found for child-perceived peer victimisation (d = .62), self-esteem (d = .45) and teacher-reported conduct problems (d = .42). Parent-reported effects on emotional, conduct problems and impact of the problems and child-reported effects on self-esteem were clinically relevant. No significant effects of Topper Training were found for prosocial behaviour and bullying. Within-participant t-tests in the intervention group between post-intervention and follow-up indicated that effects extended over a six-month follow-up period. Depression decreased significantly from post-test to follow-up. In conclusion, children with mild to severe internalising and/or externalising problems can benefit from the transdiagnostic Topper Training intervention.