Table of Contents:
Externalizing disorders like attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD) emerge in early childhood. To describe childhood externalizing psychopathology a dimensional approach is increasingly adopted. Etiologically externalizing disorders are considered as heterogeneous and associations with deficits in different psychological functions are presumed. Prevalence rates about 5.4% illustrate the wide dissemination of externalizing disorders. In clinical manifestation externalizing disorders are related to considerable impairment for the affected children and their families. Early interventions are essential to positively affect the course of externalizing disorders. The present cumulus focuses on the etiology of childhood externalizing disorders as well as on the efficacy of early parent-based interventions. Manuscript #1 examines the specificity of neuropsychological deficits in relation to ADHD and ODD symptoms. Analyses revealed specific associations between ADHD symptoms and both delay aversion and intelligence. These associations showed independent of several control variables and ODD symptoms. Concerning executive inhibitory control and sensorimotor coordination no specific associations to ADHD or ODD symptoms arose. ODD symptoms showed no significant associations with neuropsychological basic deficits that have been considered here over and above ADHD symptoms. Results are integrated in the current research framework of the etiology of externalizing disorders. Specific associations between neuropsychological deficits on the one hand and ADHD and ODD symptoms on the other hand seem to exist. The identification of subgroups with certain deficits is commented on as a focus for future research. Manuscripts #2, #3 and #4 focus on the efficacy of parent-based intervention for the treatment of childhood externalizing disorders. Manuscript #2 as a systematic review outlines the efficacy of parent-based interventions for the treatment of mental health disorders in childhood. Evidence supporting the efficacy of parent-based intervention for the treatment of internalizing as well as externalizing disorders arose. Findings concerning externalizing disorders turned out to be more extensive than results on internalizing disorders. Furthermore, they provided meta-analytic results of effects on child behavior as well as parental characteristics. However, these broad results are considerably heterogeneous. To clarify the magnitude of effects manuscripts #3 and #4 summarize all existing meta-analytic estimates via meta-meta-analyses. The results suggested moderate and stable effects of parent-based interventions on child behavior overall as well as externalizing child behavior. These positive effects showed both in parental and observational reports, which further fortifies the findings. Concerning parental characteristics analyses revealed moderate and stable effects on parenting and parental perceptions. Observational data did not confirm the positive effects on parenting though. In addition, a small and stable effect emerged for parental relationship quality. An equally small effect on parental mental health did no longer reach significance in the follow-up analyses. Heterogeneity of results and implications for future research are discussed. All things considered positive effects of early parent-based interventions on both child behavior and parental characteristics can be ascertained. Thus parent-based interventions should be implemented as evidence-based interventions in clinical practice for the treatment of childhood externalizing disorders.