At prior assessments, we did not report any comparisons for children with only co-occurring (both internalizing and externalizing) symptoms (they were combined with children with externalizing problems in analyses). In comparison to control children, we expected these children to have significant difficulties in regard to EC. We were unsure whether they would differ from control children in impulsivity because internalizing children tended to be low in impulsivity at younger ages, whereas externalizing children were high in impulsivity. Moreover, children with co-occurring problems were expected to be quite high in anger and sadness in comparison to control children. In addition, Eisenberg et al. (2001, 2004) did not compare children with solely high levels of externalizing symptoms with control children. Thus, we examined whether similar problems with EC/impulsivity and emotionality were as evident for this group of children as for children with co-occurring problems (compared with control children).
