To gain insight into the aetiology of individual differences in childhood aggression and in co-occurring behavioural and emotional problems, ACTION (Aggression in Children: unravelling gene-environment interplay to inform Treatment and InterventiON strategies; http://www.action-euproject.eu/) created a consortium with access to large childhood prospective twin, population-based and clinical cohorts. ACTION brings together multiple large cohort studies in genetically informative populations (see Table 1 and Appendix 1). The focus of ACTION is to inform on the aetiology of differences in aggression between children by unravelling its genetic architecture using univariate, multivariate and longitudinal genetic and epigenetic modelling in twin and genetic and epigenetic association studies. A strong focus of ACTION includes biomarker and metabolomics research [21].
