Examining the Effects of Early Adversity: From Infancy to Early Adulthood

• In Event: Trauma-Informed Practice as an Equitable Practice in Early Childhood Education

Abstract

Objectives/Purpose: My goal is to present the data about the timing and type of early experiences on later outcomes. I will provide evidence that early life represents a sensitive period for the effects of stress on the developing brain, and how the increased plasticity of the human brain in infancy and early childhood may increase susceptibility to adverse experiences, as well as provide opportunities for growth following adversity in the context of positive experiences. Specifically, I will use two complementary studies to demonstrate adolescent and early adult outcomes in brain development, psychopathology, language ability, cognitive functioning, adaptive functioning.

Perspective: Given the plasticity of the developing brain, experiences in early life have the potential to set the foundation for brain development and subsequent behavior. The type of exposures as well as the domains examined may be important moderators of the associations between early adversity and later functioning.

Methods: The use of two unique samples with complementary information will be used to examine the long-term outcomes associated with early adversity. The first is a sample of 178 early adolescents (ages 9-13 years) who provided interviews about their exposure to a number of different stressful events (and age of exposure), and whom underwent structural magnetic resonance imaging to obtain measures of the hippocampus. The second sample is drawn from a longitudinal study following 136 infants or young children (baseline mean age 22 months) who participated in a randomized controlled trial of foster care as an alternative to institutional care. These children, all exposed to early psychosocial deprivation were following through age 18 years and assessed for psychiatric disorders, cognitive ability, receptive language, and adaptive functioning; a never institutionalized community comparison group was also included.

Results: In sample 1, we conducted separate linear regressions based on stress severity during the two age periods (i.e., through age 5 years or age 6 or older). There was a significant association between stress severity in early childhood and left hippocampal volume (beta=-.28, t(103)=-2.93, p=.004, R-square=.08), as well as right hippocampal volume (beta=-.31, t(107)=-3.39, p<.001, R-square=.10). For severity of stress experienced in later childhood, there was no significant association between stress severity and hippocampal volume. In the second sample, for those who participated in late adolescent/early adult assessments, among those with a history of institutional care, we observed significantly higher rates of psychiatric disorder, lower IQ scores and receptive language ability, and poorer adaptive functioning relative to those without deprivation exposure. Further, for nearly all domains, children randomized into family care demonstrated better outcomes in later development than their counterparts randomized to care as usual (usually prolonged exposure to institutional care).

Significance: Exposure to early life stress increases risk for psychopathology; is associated with lower IQ; predicts poorer language and social functioning. Recent work has moved beyond descriptive accounts to consider how stress and adversity in early life, and the specificity of types of adverse experiences (e.g., threatening experiences vs. experiences of deprivation), and the age of exposures, are associated with brain development as well as behavioral outcomes.

Author

• Kathryn Humphreys, Vanderbilt University