Jenny Lee was teased, isolated and humiliated for years in elementary school.

It started in Grade 2 when she moved to Burnaby, B.C., from Hong Kong with her family when she was seven. It didn't stop until Ms. Lee switched schools in Grade 7.

Other children in her class would make fun of Ms. Lee, refuse to let her play games with them for arbitrary reasons or literally turn their backs on her. Several of the perpetrators were friends with Ms. Lee who would simply isolate her whenever they felt like it.

Story continues below advertisement

"I felt really humiliated," she said.

Now 25 and a teacher, Ms. Lee is finally able to understand what happened to her during those difficult years at elementary school: She was bullied.

"I don't think bullying was as much of a …hot topic. People just didn't know what it was at the time," Ms. Lee said in a recent interview. "I never really had considered myself as being bullied. When I describe [it] to people, I say I really didn't have a good time in elementary school."

Ms. Lee, an elementary teacher in Kingston, is like many of the countless young Canadians who have at some point found themselves the target of schoolyard bullies.

New research suggests that females such as Ms. Lee may be particularly vulnerable to bullying from other females, even as rates of male bullying decline. It's a troubling finding that highlights where parents, educators and policy makers may need to focus their efforts to counter the effects of school-related bullying.

A comprehensive report released last month by researchers from the Toronto-based Centre for Addiction and Mental Health found that while overall rates of bullying have remained relatively stable in recent years, some significant gender disparities have emerged.

The report, called the Ontario Student Drug Use and Health Survey, has been conducted every two years since 1977, making it the longest continuing survey of young people in Canada and one of the longest in the world. Nearly 9,300 students in Grades 7 to 12 from 181 different Ontario schools participated in the most recent survey, which was conducted from October, 2010, to June, 2011.

Story continues below advertisement

The study found that nearly one-third, or 29 per cent, of students reported being bullied since the start of the school year.

The overall rates haven't really changed since 2003, the first year CAMH monitored bullying at school. But the survey found that females are more likely to be bullied. Thirty-one per cent of adolescent girls reported being victimized in the most recent survey, compared to 26 per cent for boys.

Online or cyber-bullying was also much more common among females, with 28 per cent of girls reporting being targeted by cyber-bullying compared to just 15 per cent of boys.

The number of boys who report being bullied or who have bullied others has dropped since tracking began in 2003, according to Robert Mann, a senior scientist at CAMH and lead investigator of the study.

This raises several questions: Do boys get along better than girls? Have programs aimed at curbing bullying failed to reach girls?

The answers are not entirely clear, but suggest the style of bullying preferred by boys and girls may help explain the gender differences.

Story continues below advertisement

"The problem is girls do it all underneath the surface," said Haley Higdon, a facilitator with the SNAP for Schools program.

The SNAP (Stop Now and Plan) model is designed to help reach children with behavioural problems or other issues. As a facilitator, Ms. Higdon works in classrooms in the Toronto District School Board. Often, the behavioural problems she encounters stem from bullying.

With boys, bullying is typically much easier to detect because male bullies often resort to physical measures, such as fighting. With girls, the behaviour can be much more subtle, making it more difficult for teachers to detect.

Ms. Higdon recalls meeting one girl in a classroom who didn't even realize she was being bullied.

The bully was her friend, a popular and charming girl in the same class. The bully had a habit of bringing presents to school for her friends. Once she gave the gifts, however, the bully would surreptitiously take them back and place them in the backpacks of other girls in order to frame them for stealing. Finally, when several girls began reporting this to the teacher, the bully's behaviour was recognized.

But even after the girl was singled out, her father couldn't believe his daughter was actually a bully. Ms. Higdon, who sat in on a meeting with the father and school officials, said he kept pointing out how social his daughter was and the fact that she was well-liked and had good marks.

Story continues below advertisement

"Girls are a lot more covert," Ms. Higdon said. "Their threatening behaviour can go under the table."

Bullying can take on many forms. It's not just one child pushing another in the schoolyard – it is any aggressive or unwanted behaviour that involves a real or perceived imbalance in power, according to StopBullying.gov, a U.S. government website.

This could mean schools and parents need to adjust their approach when it comes to bullying. It might be difficult to spot a bully, or a child who is being targeted. The SNAP for Schools program focuses on teaching assertiveness skills so children can help defend themselves. Teachers are also encouraged to talk about bullying and read children's books on the subject.

Dr. Mann notes that it's important for children to come forward if they are being bullied.

"Tell your parents, tell your teachers," he said. "Don't suffer in silence because this is something that should not be happening."

In Ms. Lee's case, the bullying ended once her parents transferred her to a private school, one they thought could give her a better education. But she said the impact from the experience has remained with her and she hopes she can use what she learned to help the students she teaches in her classroom.