UNLOCKING THE HETEROGENEITY OF EXTERNALIZING PROBLEMS ACROSS EARLY CHILDHOOD:UNITING NEUROBIOLOGICAL, PARENTING, AND DEVELOPMENTAL PERSPECTIVES

Open Access
Author:
Fortunato, Christine Karen
Graduate Program:
Human Development and Family Studies
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
September 13, 2011
Committee Members:
  • Lisa M. Gatzke-Kopp, Committee Chair
  • Douglas A. Granger, Committee Chair
  • Mark T. Greenberg, Committee Member
  • Nilam Ram, Committee Member
  • Karen Bierman, Committee Member
Keywords:
  • parenting
  • early childhood
  • development
  • HPA
  • cortisol
  • externalizing problems
  • comorbidity
  • anxiety
Abstract:
Heterogeneity in externalizing behaviors such as conduct problems impedes the elucidation of underlying developmental mechanisms. Recent studies suggest that individuals exhibiting conduct problems may show entirely discrepant patterns of biological vulnerabilities depending on whether they have comorbid internalizing problems or not. However, no research to date has examined this from a developmental perspective. The current study examines theoretically derived hypotheses regarding the developmental risk pathways that differentiate children with conduct problems who do and do not manifest comorbid anxiety. Biological vulnerability was examined with respect to blunted or exacerbated stress responsivity. Salivary cortisol was collected in response to a stressful task at 7, 15, and 24 months of age. Additionally, home visitors reported children’s behaviors at each time point, and parenting styles were observed in a structured interaction with their child. Results showed that children with conduct problems only at 5 years of ages were characterized by the exacerbated stress responsivity at 7 months of age followed by blunted stress responsivity at 24 months old. In contrast, children with comorbid internalizing problems were typified by the interrelationship of heightened stress responsivity and high behavioral approach tendencies at 15 months of age. While both children with and without comorbid anxiety displayed exacerbated stress responsivity with greater exposure to intrusive parenting, the developmental time points that this biological sensitivity to context became apparent was different. The present study provides a better understand of the developmental mechanisms in that undergird distinct externalizing problems phenotypes with and without comorbid internalizing problems in early childhood. Overall, these findings suggest that it may be more efficacious for intervention programs to target biological, behavioral, and parenting domains of risk at key development time points to prevent the later development of distinct conduct problem phenotypes.