The purpose of the study was to examine the relations of effortful control (EC), impulsivity, and negative emotionality to at least borderline clinical levels of symptoms and change in maladjustment over four years. Children's (N = 214; 77% European American; M age = 73 months) externalizing and internalizing symptoms were rated by parents and teachers at 3 times, 2 years apart (T1, T2, and T3) and were related to children's adult-rated EC, impulsivity, and emotion. In addition, the authors found patterns of change in maladjustment were related to these variables at T3 while controlling for the T1 predictor. Externalizing problems (pure or co-occurring with internalizing problems) were associated with low EC, high impulsivity, and negative emotionality, especially anger, and patterns of change also related to these variables. Internalizing problems were associated with low impulsivity and sadness and somewhat with high anger. Low attentional EC was related to internalizing problems only in regard to change in maladjustment. Change in impulsivity was associated with change in internalizing primarily when controlling for change in externalizing problems.

The authors examined the relations of maternal supportive parenting to effortful control and internalizing problems (i.e., separation distress, inhibition to novelty), externalizing problems, and social competence when toddlers were 18 months old (n = 256) and a year later (n = 230). Mothers completed the Coping With Toddlers' Negative Emotions Scale, and their sensitivity and warmth were observed. Toddlers' effortful control was measured with a delay task and adults' reports (Early Childhood Behavior Questionnaire). Toddlers' social functioning was assessed with the Infant/Toddler Social and Emotional Assessment. Within each age, children's regulation significantly mediated the relation between supportive parenting and low levels of externalizing problems and separation distress, and high social competence. When using stronger tests of mediation, controlling for stability over time, the authors found only partial evidence for mediation. The findings suggest these relations may be set at an early age.