Background: Irritable mood has recently become a matter of intense scientific interest. Here, we present data from two samples, one from the United States and the other from the United Kingdom, demonstrating the clinical and research utility of the parent- and self-report forms of the Affective Reactivity Index (ARI), a concise dimensional measure…

Background: While there is considerable evidence of income gradients in child and adolescent behaviour problems, evidence relating to children and young people's emotional difficulties is more mixed. Older studies reported no income differentials, while recent reports suggest that adolescents from low-income families are more likely to experience…

Objective: Callous-unemotional (CU) traits in children and adolescents are increasingly recognized as a distinctive dimension of prognostic importance in clinical samples. Nevertheless, comparatively little is known about the longitudinal effects of these personality traits on the mental health of young people from the general population. Using a…

Background: Assessments of child psychopathology commonly rely on multiple informants, e.g., parents, teachers and children. Informants often disagree about the presence or absence of symptoms, reflecting reporter bias, situation-specific behaviour, or random variation in measurement. However, few studies have systematically tested how far…

Background: The use of similar standardised measures of psychopathology for population surveys permits cross-cultural comparisons. However, interpretation of findings can be challenging because rating thresholds may differ across cultures. By combining questionnaire and interview data, we explore whether lower questionnaire scores in Norway as…

Background: Existing evidence points to a substantial rise in psychosocial disorders affecting young people over the past 50 years (Rutter & Smith, 1995). However, there are major methodological challenges in providing conclusive answers about secular changes in disorder. Comparisons of rates of disorder at different time points are often…