A psychometric and validity study of callous-unemotional traits in 2.5 year old children.

Callous-unemotional (CU) traits are associated with severe and stable antisocial behaviour in childhood and adolescence. In order to understand the earliest origins of CU traits we need first to know whether measurement is reliable and valid in young children. This study evaluated the psychometric properties and validity of a CU traits measure generated from existing child problem behaviour scales at age 2.5 years. The participants were members of an epidemiological longitudinal study starting in pregnancy. Items from the Antisocial Process Screening Device and other problem behaviour scales were subjected to exploratory and confirmatory factor analysis. Structural equation modelling was used to test whether age 2.5 CU traits showed incremental validity in predicting aggression at age 5. The CU measure showed acceptable psychometric properties, factorial invariance by sex and good stability. Incremental prediction to later aggression was evident in girls, whereas boys showed strong continuity in aggression not found for girls.