Relatively few investigators have examined relations of children’s negative emotionality with pure internalizing problems, pure externalizing problems, and co-occurring problems, especially in multiple assessments across time. It is possible that sadness is sometimes linked with externalizing problems because many children with externalizing problems also have internalizing problems. Eisenberg, Sadovsky, et al. (2005) found relations of sadness with both pure internalizing problems and with externalizing problems (co-occurring and pure combined) and that sadness was more common for pure internalizers than for pure externalizers. Eisenberg, Sadovsky, et al. (2005) did not compare children with only co-occurring problems to a control group. Co-occurring problems, but not pure externalizing problems, may be associated with sadness, whereas anger may be linked to externalizing problems regardless of co-occurring internalizing problems. It is important for researchers to more closely study children with co-occurring externalizing and internalizing symptoms and to learn whether relations of one type of these symptoms to EC, impulsivity, and emotion are maintained when controlling for the other type.
