In recent years, a steadily increasing volume of data has demonstrated that peer victimization – the clinical term for bullying – impacts hundreds of millions of Massachusetts children and adolescents, with the effects sometimes lasting years and, possibly, decades. The problem is even recognized as a global health challenge by the World Health Organization and the United Nations.
And yet, researchers maintain there is still a limited understanding of how the behavior may physically shape the developing brain.
Bullying is usually defined as repeated and intentional verbal, physical, and anti-social behavior that seeks to intimidate, harm, or marginalize someone perceived as smaller, weaker, or less powerful. Among younger children, common forms of bullying include abusive language and physical harm. This behavior may grow subtler with age as adolescent bullies routinely exclude, insult, and mock their targets. Sometimes this behavior escalates into “mobbing” among groups of bullies in school, work, or cyberspace.
Researchers believe more than 3.2 million American students experience bullying every year. That’s about 1 percent of the nation’s total population. Among these students, about 10 to 15 percent experience “chronic” or persistent bullying that will last more than six continuous months. Experiencing chronic peer victimization is associated with lower academic achievement, higher unemployment rates, depression, anxiety, post-traumatic stress disorder, substance abuse, and self-harm and suicidal thoughts.
Most of the research into the neurobiological processes that might contribute to these negative health outcomes has occurred in the past decade, much of it focused on bullying’s impact on the body’s stress response system.
A recent paper published in the journal Molecular Psychiatry sheds some light on a different area: brain architecture. The trauma stemming from chronic bullying can affect the structure of the brain, according to longitudinal magnetic resonance imaging (MRI) data collected by an international team based at King’s College London. The findings echo previous research, which has demonstrated similar changes in children and adults who experienced what’s known as “child maltreatment” – neglect or abuse by adult caregivers.
Long-term changes to the brain’s structure and chemistry are an indicator “of how sinister bullying is” according to clinical psychologists.
Analyzing changes in brain volume at age 19, they found that participants who experienced chronic bullying had significantly steeper decreases in the volume of two regions involved in movement and learning the left putamen and left caudate with the former showing the stronger effect. These participants also experienced higher levels of generalized anxiety.
The relationship between peer victimization and generalized anxiety was due at least in part to these steeper decreases in volume. This suggests that the areas of the brain are getting almost too small.