Grade-School Bullying Takes a Toll on the Adolescent Brain, Study Finds
The marks of childhood bullying don't fade; they imprint themselves on a student's brain, according to new research presented at the Society for Neuroscience annual meeting here this morning.
Researchers from Children's Hospital Los Angeles and the University of Southern California Keck School of Medicine tracked 83 healthy children from age 9 through age 14, using both the Child Friendship Questionaire—a measure of social relationships and physical and social harrassment—and structural scans of the development of different regions of their brains at different ages.
"Before [social media], your bullies at school stayed at school," said Alina Arakelian, a pediatrics research assistant at Children's Hospital and a co-author of the study. "Now, through social media, they follow you everywhere," which can boost the severity and effects of peer harassment.
The researchers found that students who reported high levels of peer harrassment at age 9 showed significant differences in brain structures at age 14. The amygdala, associated with the ability to process emotions and react to stress, was larger in volume among 14-year-olds who had been bullied as children, with the effect greater for boys than girls. Moreover, previously bullied adolescents had thinner temporal and prefrontal cortexes, areas critical for processing information and regulating behavior. This thinning was seen in both sexes but was stronger in girls than boys.
The researchers plan to dig into those sex-based differences in a follow-up study, Arakelian said, but she ventured a guess about the different reactions. "Maybe males are not processing the harassment the same way as females," she said. "For girls, they tend to internalize, so it may be changing the way they see themselves in connection to other people," while the greater increase in amygdala volume for boys may be a sign of faster reactiions to perceived threats—both found to be common responses to bullying among teenagers.
The study comes in the wake of a flood of new research on the brain changes that can be wrought by early, "toxic" stress, such as parental neglect or abuse. While stress from peer harassment is not generally as severe a trauma as say, the death of a parent, these results suggest even more moderate chronic stress can affect students' brain development in ways that could interfere with learning and behavior in school.
The study gives yet more evidence of the need for educators to understand and disrupt cycles of bullying in school.