The Impact of Trauma and Early Life Adversity on Neural Structural Alterations during Development

Abstract

Childhood maltreatment is associated with various adverse outcomes in later stages of life including non-specific forms of psychopathology, deteriorated physical health, and poor psychosocial functioning. The developing brain is marked by high plasticity suggesting the potential for chronic life stressors to have a greater impact during childhood. However, previous studies on childhood maltreatment and brain structures are often limited by case-control designs or the failure to capture the dimensional nature of adversity. Furthermore, despite the high co-occurrence of stressors, studies often examine single types of stressors in isolation. The current thesis aimed to investigate the association between early life stressors and brain structures using cortical thickness and gray matter volume (GMV) in a large sample of children from the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®). Study 1 focused on trauma exposure using a latent factor derived from DSM-5 traumatic events and its relationship with the brain structures. Trauma exposure was associated with thinner cortices in frontal regions as well as thicker cortices in cingulate regions and these findings were largely consistent after controlling for measures of socioeconomic status (SES). Trauma exposure was associated with smaller GMV in the amygdala and putamen, but results disappeared after controlling for SES measures. Study 2 took a broader approach in defining early life adversity by delineating general and specific factors of environmental stressors using a bifactor model. The bifactor modeling identified a general factor that represents common variance across multiple environmental stressors as well as specific factors of familial risk, interpersonal community, neighborhood deprivation, and urbanicity. The general factor was associated with cortical thinning in frontal, parietal, and occipital regions as well as globally smaller cortical and subcortical volumes. The specific factor of neighborhood deprivation was associated with cortical thinning in frontal, temporal, and parietal regions, which are implicated in executive functioning and language processing. The specific factor of urbanicity was associated with thicker cortices in frontal, temporal, and parietal regions as well as globally larger cortical and subcortical volumes. The current thesis suggests that childhood trauma and environmental stressors may be important risk factors for structural aberrations in the developing brain.