Bullying the Brain? Longitudinal Links Between Childhood Peer Victimization, Cortisol, and Adolescent Brain Structure

Abstract

Background: Childhood peer victimization is a stressful life experience associated with long-lasting adverse psychological consequences. While there is some evidence that victimization is associated with alterations in brain function, little is known about effects on brain structure. This study explored the relationships between childhood peer victimization, cortisol, and adolescent ventrolateral prefrontal cortex (vlPFC) structure in a sample of healthy children.Methods: A total of 50 (Mage = 9.29 years at baseline) children participated in this longitudinal study. We examined whether diurnal cortisol levels (assessed at baseline) moderated the link between children’s self-reported peer victimization (assessed at baseline) and vlPFC surface area, gray matter volume, and thickness 5 years later.Results: For boys, cortisol levels moderated the association between victimization and brain structure. For boys with a low daily cortisol output (assessed as area under the curve; AUC), high victimization was associated with a smaller right vlPFC surface area, and for boys with a high AUC, high victimization was associated with a larger right vlPFC surface area. In addition, for boys with a steeper diurnal slope, high victimization was associated with a smaller right vlPFC surface area, and for boys with a low flatter diurnal slope, high victimization was associated with a larger right vlPFC surface area.Conclusion: These results indicate the differential influence of cortisol on the relationship between victimization and brain structure. Findings suggest that victimization may have differential effects on brain development in boys who are more versus less biologically sensitive to stress.

How does peer adversity “Get inside the Brain?” Adolescent girls’ differential susceptibility to neural dysregulation of emotion following victimization

“…To assess sensitivity to rejection, participants completed a subset of items from the Children's Rejection Sensitivity Questionnaire (CRSQ; Downey et al, 1998) prior to the scan session. The original measure includes 12 vignettes; given the focus of this study on peer victimization, youth completed six vignettes that were specific to potential peer rejection (e.g., "Imagine you are in your classroom, and everyone is splitting up into groups to work on a special project together.…”

“…A composite rejection sensitivity score was then computed by averaging the mean anxious-rejection and anger-rejection scores, with higher scores indicating more sensitivity to rejection. This measure has established convergent and discriminant validity (Downey et al, 1998;London et al, 2007).…”

Frequent Bullying Involvement and Brain Morphology in Children

“…Previous work has already shown how early-life adversities, such as abuse, early life stress, quality of maternal care, and growing up in institutional care, impact cortical and subcortical development in children (13–15). Despite this work demonstrating the sensitivity of structural neuroimaging to detect subtle morphological features of typical and atypical brain development, few studies have explored to what extent bullying involvement is associated with brain morphology and brain structure (16, 17). More substantial focus has been given to aspects of peer and social interaction using functional MRI (18) where, for example, anterior cingulate and prefrontal cortices have been implicated with differential functional activity in the context of exposure to social exclusion (19, 20).…”

Cyberbullying and Adolescent Neurobiology

“…Furthermore, the lowest cortisol secretion was observed in serious cyberbullies ( González-Cabrera et al, 2017 ). Similarly, du Plessis et al (2019) found that cortisol moderated the relationship between traditional bullying childhood victimization and adolescent ventrolateral prefrontal cortex (vlPFC) structure, and that this was dependent on gender. That is, boys with higher experiences of childhood victimization showed high cortisol levels and a smaller vlPFC structure, compared to those with low cortisol and low victimization.…”

“…Whilst both these studies suggest that there are biological markers associated with different roles in cyberbullying, and that cortisol levels could be particularly important in regard to brain development during adolescence, further research is needed in order to understand how this may influence adolescent brain development over time. The study by du Plessis et al (2019) also focused on traditional bullying rather than cyberbullying.…”