Researchers surveyed 2,680 student from Victoria, Australia, twice in 8th grade and once in 9th grade. Participants reported their symptoms of anxiety or depression, and were categorized as being victimized if they reported getting bullied at either or both survey times in 8th grade.

Of those surveyed, 51 percent of students had been victimized by the second survey in 8th grade. Approximately 18 percent of students reported symptoms of anxiety and depression, and students were significantly more likely to report such symptoms if they'd been victimized. Results of the study were published in the September 1st issue of the British Medical Journal.

The association was found more significant among girls. A depression and anxiety prevention effort might be well served by reducing victimization and bullying in schools, the authors write.

"These findings have implications for how seriously the occurrence of victimization is treated and for the focus of interventions aimed at addressing mental health issues in adolescents," according to the report.

Reducing the frequency of bullying in schools could have a significant impact on the mental health of youth, according to the researchers.