Teens who are often bullied may be left with shrinkage in key parts of their brain, increasing their risk for mental illness, European researchers report.
They said such shrinkage eventually appears to create a growing sense of anxiety, even after taking into account the possible onset of other mental health concerns, such as stress and/or depression.
"We don’t know how early in life these brain changes begin," said study author Erin Burke Quinlan. "But the earlier bullying is identified, and the sooner it can be dealt with, the better."
Her team analyzed brain scans of nearly 700 14- to 19-year-olds in England, Ireland, France and Germany. The teens were part of a long-term project called IMAGEN that is studying adolescent brain development and mental health.
"We found that the relationship between chronic peer victimization — an umbrella term that includes bullying — relates to the development of anxiety partly via changes in the volume of brain structures," said Quinlan, an IMAGEN project coordinator at the Center for Population Neuroscience and Precision Medicine at King’s College London.
Researchers aren’t sure if the bullied teens’ brain shrinkage is permanent or if it may be reversible.
"We would need to follow adolescents into adulthood to start to answer this question," Quinlan said. "In this study we did not look at changes in brain activity, which could be a mechanism by which the effects of bullying on mental health could persist even if structural changes were halted or reversed."
And that, Quinlan said, means the focus should be on preventing bullying in the first place. "Or at least, stopping bullying as soon as it’s been identified," she added. "While prevention still takes resources and education, it’s likely easier than trying to reverse brain changes years later."
Quinlan noted that as many as 3 teens in 10 are affected by bullying, some almost daily.
The participants completed surveys at ages 14, 16 and 19 to gauge their exposure to bullying. Brain scans were done at ages 14 and 19.
Thirty-six students — about 5 percent — were characterized as victims of chronic bullying.
By age 19, those teens had reduced size in two key regions of the brain, compared to age 14. The two affected regions — known as "caudate" and "putamen" — are involved in regulation of motivation, attention and emotional processing. However, the researchers only found an association between bullying and brain changes.
Quinlan suggested parents who suspect bullying is taking place speak with a child’s principal or teacher about it. But, she cautioned, victims are often reluctant to tell anyone what’s happening.
"Sometimes a child may not verbally admit they’re being bullied, so parents can watch out for nonverbal cues or changes in their child’s behavior or their attitudes towards school," Quinlan said. "A mental health professional could be useful to help a child develop tools to deal with being bullied."
She and her colleagues reported their findings in the journal Molecular Psychiatry.
Stephen Russell is a professor of child development at the University of Texas at Austin. He said the findings suggest "an obvious link between bullying, stress and long-term health," and called the study important.
"Hopefully," Russell added, "this will be additional data that will help change the minds of people who think that bullying is ’natural’ or a normal part of growing up."
He said the research should underscore the importance of efforts to reduce bullying at the individual and school levels. Russell said several strategies have proven successful.
"Many, many youth experience bullying and grow up to be thriving adults," he said. "So even though bullying may even (affect) the structure of our brains, that doesn’t mean that we don’t have the ability to cope and compensate. And the very things that bullying may change — like attention or sensitivity — could be things that people learn to use to their advantage."