Disentangling the Impact of Childhood Adversity: Unique Effects of Deprivation and Threat Open Access

LoPilato, Allison (2017)

Permanent URL: https://etd.library.emory.edu/concern/etds/8049g576q?locale=en
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Abstract

It is well established that childhood adversity increases risk for multiple forms of psychopathology. However, less is known about the developmental mechanisms linking childhood adversity to psychopathology, and whether those mechanisms are specific to different types of adversity. Prevailing cumulative-risk models treat childhood adversity as a unitary construct, which implicitly assumes that very different experiences influence development similarly. However, emerging research suggests that specific types of adversity may have unique effects. Identifying dimensions of experience that cut across multiple types of adversity, based on neuroscience principles of experience-dependent plasticity, may be a more effective strategy for delineating the impact of adversity experiences on developmental processes. The current dissertation tested a novel conceptual model distinguishing childhood adversity along dimensions of threat and deprivation, and examined their specific associations with (1) corticolimbic structure and (2) stress processes. Results from the dimensions of adversity model were compared to prevailing cumulative-risk models to determine the relative merits of the two approaches. Participants were drawn from a large study of youth at risk for serious mental illness with variability in exposure to childhood adversities. Study 1 investigated whether threat and deprivation were differentially associated with corticolimbic structure. Results revealed deprivation-specific associations with smaller cortical and hippocampal volumes, and an interactive effect of threat and deprivation on superiorfrontal cortical thickness. Study 2 examined whether stress sensitivity mediates the association between childhood adversity and basal cortisol and whether these associations differ by adversity dimension and sex. Results indicated that both threat and deprivation were associated with increased stress sensitivity, which subsequently predicted higher basal cortisol levels; however threat effects were specific to females. Across both studies, the dimension-specific associations were masked in the prevailing cumulative-risk approaches. These results highlight the importance of assessing the specific nature of adversity and provide preliminary support for the differentiation of threat and deprivation dimensions.

Table of Contents

Dissertation General Introduction…………………………………..………………….…1

Study 1: Differential Associations of Deprivation and Threat with Corticolimbic

Structure...................................................................................17

Introduction……………………………………………………………………....................19

Method……………………………………………………………………….........................27

Results……………………………………………………………………...........................32

Discussion…………………………………………………………………..…....................34

References………………………………………………………………...….....................43

Appendix A: Tables…..……..…………………………………………....…….............52

Appendix B: Figures……………………………………………………...….................60

Study 2: The Conditional Effect of Childhood Adversity on Stress

Processes........….......................................................................63

Introduction……………………………………………………………...……..................65

Method…………………...……………………………………………………....................70

Results……………………………………………………………………....…...................75

Discussion…………………………………………………………………….....................78

References…………………………………………………………………..…..................84

Appendix C: Tables…..……..…………………………………………………..............89

Appendix D: Figures…………………...……………………………………................92

Dissertation General Conclusion….………………………………..…………….......98

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