Frequent Bullying Involvement and Brain Morphology in Children

• In Event: 1-038 - Neural Underpinnings of Childhood and Adolescent Adverse Social Experiences With Peers

Integrative Statement

Background
Bullying amongst peers during childhood has emerged as an important public health concern. While estimates vary considerably by geographical region and severity of involvement, numerous reports suggest upwards of 10% of youth are involved in severe or frequent bullying. Importantly, consequences of bullying involvement have been consistently reported, including an increased risk for psychopathology, substance use, and suicidality in short- and long-term follow-up studies. The presence of such persistent sequelae raises the possibility of an underlying neurobiological substrate that could prove crucial in explaining or predicting poor long-term outcomes. However, in vivo neuroimaging assessments of bullying involvement in children have been limited. In this talk, we add to this literature by describing how frequent bullying involvement is related to brain morphology in children. We hypothesized children involved in bullying would show differences in cortical areas involved in threat perception/sensitivity, fear, anxiety, emotional face processing, and emotional (dys)regulation (e.g., prefrontal cortex, cingulate gyrus, fusiform face area, and insula).
Methods
This study was performed using data from the Generation R Study, a prospective birth cohort in Rotterdam, the Netherlands. Of the 3,992 children who visited our research center for a neuroimaging assessment at age 10, 806 were excluded due to unusable imaging data (artifact, motion, or incidental finding), and another 583 did not have data on child bullying involvement, leaving 2,603 datasets for analysis. At the age of 7, physical, verbal, and relational bullying involvement (separately for perpetrator and victim) were assessed by asking the child’s parent and/or the child’s teacher. Children were classified as involved if their parent or teacher indicated they were bullied or they themselves bullied other children once per week or more, representing frequent involvement. Children classified as both a bully and as a victim were reclassified as bully-victims. High-resolution structural neuroimaging data were collected using a single 3-Tesla MRI system when children were 10 years old. Imaging data were processed through FreeSurfer, and data were visually inspected for reconstruction accuracy. Whole-brain, vertex-wise linear regression analyses of cortical thickness were run using an in-house library for the R Statistical Software. Regression models were adjusted for a number of potential confounding factors, including IQ, socioeconomic factors, and childhood behavioral problems. Analyses were adjusted for multiple comparisons using Monte Carlo simulations.
Results
Children classified as victims showed thicker cortex in the fusiform gyrus compared to those uninvolved in bullying (Figure 1). Results remained consistent after adjusting for various confounding factors (pCFT = 0.001). Children classified as bullies showed thinner cortex in the cuneus regions. However, this difference was only significant as a suggestive correction for multiple comparisons (pCFT = 0.005). No differences were observed in bully-victims.
Discussion
The fusiform area, known to be involved in (emotional) face processing, showed thicker cortex in victims. These data demonstrate disrupted cortical morphology in those bullied by their peers, and may offer cues to future work investigating the neurobiological underpinnings of associated and persistent problems later in life. Future work should utilize longitudinal neuroimaging data to concretely ascertain the different developmental trajectories involved.

Authors

• Ryan Muetzel, University Medical Center Rotterdam, the Netherlands
  Presenting Author

• Rosa Mulder, Leiden University
  Non-Presenting Author

• Tonya White, University Medical Center Rotterdam
  Non-Presenting Author

• Pauline Jansen, Erasmus MC-University Medical Center Rotterdam, The Netherlands
  Non-Presenting Author

• Henning Tiemeier, Harvard TH Chan School of Public Health, Boston
  Non-Presenting Author