Cortisol output in response to emotion induction procedures was examined at child age 24 months in a prospective longitudinal sample of 1,292 children and families in predominantly low-income and nonurban communities in two regions of high poverty in the United States. Multilevel analysis indicated that observed emotional reactivity to a mask presentation but not a toy removal procedure interacted with sensitive parenting to predict cortisol levels in children. For children experiencing high levels of sensitive parenting, cortisol output was high among children exhibiting high emotional reactivity and low among children exhibiting low emotional reactivity. For children experiencing low levels of sensitive parenting, cortisol output was unrelated to emotional reactivity.

Cortisol output in response to emotion induction procedures was examined at child age 24 months in a prospective longitudinal sample of 1,292 children and families in predominantly low-income and nonurban communities in two regions of high poverty in the United States. Multilevel analysis indicated that observed emotional reactivity to a mask presentation but not a toy removal procedure interacted with sensitive parenting to predict cortisol levels in children. For children experiencing high levels of sensitive parenting, cortisol output was high among children exhibiting high emotional reactivity and low among children exhibiting low emotional reactivity. For children experiencing low levels of sensitive parenting, cortisol output was unrelated to emotional reactivity.

BACKGROUND: Approximately one third of children who meet criteria for conduct problems (CP) are also characterized by elevated callous-unemotional (CU) traits. This subgroup is at elevated risk for more pervasive and extreme levels of later antisocial behavior and has been characterized by a fearlessness temperament and blunted stress psychophysiology at older ages. The objective of this study was to examine group differences in fear reactivity and stress psychophysiology in infancy among children classified as having CP with CU (CP + CU), CP without CU (CP only), or no CP in later childhood. METHODS: A birth cohort study (n = 1,292) was followed longitudinally from birth through first grade. Behavioral fear, baseline heart period (HP) and respiratory sinus arrhythmia (RSA), and pretask, 20-min posttask, and 40-min posttask salivary cortisol were assessed at 6 and 15 months of age around a fear challenge task. CP and CU were assessed by maternal report at first grade and children were classified into CP and CU groups if they scored in the upper 10(th) percentile of these ratings. RESULTS: No group differences were observed in children at 6 months of age. However, at 15 months of age children with later CP + CU displayed greater high-intensity fear behavior, higher pretask and overall cortisol levels, and lower levels of HP and RSA compared to children with CP only and children with no CP. CONCLUSIONS: The discrepancy between the biobehavioral correlates of conduct problems with callous-unemotional traits in infancy and those reported from studies of older children and adults suggests that the etiology of this behavioral phenotype may be more complex than a simple genetic maturation model.

Background

Approximately one third of children who meet criteria for conduct problems (CP) are also characterized by elevated callous-unemotional (CU) traits. This subgroup is at elevated risk for more pervasive and extreme levels of later antisocial behavior and has been characterized by a fearlessness temperament and blunted stress psychophysiology at older ages. The objective of this study was to examine group differences in fear reactivity and stress psychophysiology in infancy among children classified as having CP with CU (CP + CU), CP without CU (CP only), or no CP in later childhood.

Methods

A birth cohort study (n = 1,292) was followed longitudinally from birth through first grade. Behavioral fear, baseline heart period (HP) and respiratory sinus arrhythmia (RSA), and pretask, 20-min posttask, and 40-min posttask salivary cortisol were assessed at 6 and 15 months of age around a fear challenge task. CP and CU were assessed by maternal report at first grade and children were classified into CP and CU groups if they scored in the upper 10(th) percentile of these ratings.

Results

No group differences were observed in children at 6 months of age. However, at 15 months of age children with later CP + CU displayed greater high-intensity fear behavior, higher pretask and overall cortisol levels, and lower levels of HP and RSA compared to children with CP only and children with no CP.

Conclusions

The discrepancy between the biobehavioral correlates of conduct problems with callous-unemotional traits in infancy and those reported from studies of older children and adults suggests that the etiology of this behavioral phenotype may be more complex than a simple genetic maturation model.