Study links bullying to cognitive deficits, brain changes

They lurk in hallways, bathrooms, around the next blind corner. But for the children they have routinely teased or tormented, bullies effectively live in the victims' brains as well — and not just as a terrifying memory.

Preliminary evidence shows that bullying can produce signs of stress, cognitive deficits and mental-health problems.

Now University of Ottawa psychologist Tracy Vaillancourt and her colleagues at McMaster University in Hamilton, Ontario plan to scan the brains of teens who have been regularly humiliated and ostracized by their peers to look for structural differences compared with other children.

"We know there is a functional difference. We know their brains are acting differently, but we don't know if it is structural as well,"said Vaillancourt, an expert in the biology of bullying.

She says she hopes her work will legitimize the plight of children who are bullied, and encourage parents, teachers and school boards to take the problem more seriously.

Vaillancourt has been following a group of 17-year-olds since they were 12. All 70 of the children were routinely bullied during those years — teased, harassed, threatened or excluded.

Physical violence is relatively rare, she says, because their tormentors are smart enough to know it will get them into trouble.

"For many of these kids, every day is a nightmare,"she said. They go to school and no one will talk to them. Someone deliberately bumps into them in the hallway, and all the other children laugh. They get called horrible names.

The researchers will start with brain scans of 15 of the extreme cases, like the child who stood in her gym uniform while other kids put her school clothes in the toilet and urinated on them.

There are also teenagers in the study who have been bullied for five straight school years.

The scientists have already shown that children who are bullied are more likely than other kids to have cognitive deficits.

They score lower on tests that measure verbal memory and executive function, a set of skills needed to focus on a task and get the job done. Mental-health problems, such as depression, are also more common.

Vaillancourt suspects they will also have a smaller hippocampus, a part of the brain involved in memory. Depression has been shown to be related to a smaller hippocampus. As well, animal studies have shown that chronic high levels of stress can kill brain cells. Vaillancourt says this kind of damage may help explain why children who are bullied often perform poorly academically.

She will also be looking for a smaller prefrontal cortex, which plays a role in being able to pay attention and other executive functions.

These kinds of differences have been documented in functional magnetic resonance imaging, or MRI, studies of children who have been neglected or abused. Vaillancourt suspects the chronic stress of being bullied will have a similar impact.

She and her colleagues have already published research showing that boys who are bullied tend to produce more of the stress hormone cortisol. It is as if their system is in permanent overdrive.

It's the opposite for the girls; they tend to produce less cortisol than average, as though their stress response system is overly subdued.

"At some point, their brains stop reacting,"said Vaillancourt, who holds a Canada Research Chair in children's mental health and violence prevention.

These changes to the brain's stress response system may be linked to the higher rates of depression among children who are regularly picked on by their peers, especially girls. The adolescent years are when peer relations are most important and when girls, more than anything, want to belong, Vaillancourt says.

Distributed by Scripps Howard News Service, www.scrippsnews.com.