A study conducted by Canadian researchers determined that teens are more likely to consider suicide if they've experienced classmates taking their own lives, regardless of how well they knew them.

According to the World Health Organization, the global mortality rate for suicide is 16 for every 100,000 people. Suicide rates have swelled by 60 percent worldwide in the past 45 years.

"Our study has several strengths. First, we used a large, nationally representative prospective cohort to examine the association between exposure to suicide and suicidality outcomes," explained lead author Dr. Ian Coleman.

"Second, we included 2 important types of suicide exposure (schoolmate's suicide and personally knowing someone who died by suicide) along with several relevant covariates."

Coleman and his colleagues from the University of Ottawa used the Canadian National Longitudinal Survey of Children and Youth 1998/99 and 2006/07 for the basis of their study.

In total, 22,064 Canadian teenagers were surveyed including 8,766 aged 12 to 13 years, 7,802 aged 14 to 15 years and 5,496 aged 16 to 17 years. One survey was taken at the start of their research and a follow up was taken after two years had passed.

Students received questionnaires asking if anyone in their class has committed suicide, if they personally knew someone who committed suicide, and if they themselves had seriously considered taking their own life. The research team also identified traumatic life events and socioeconomic status as possible contributing factors.

Their findings determined that, of those who were exposed to suicide, 15.3 percent of students aged 12 to 13, 14.2 percent of students aged 14 to 15, and 15.1 percent of students aged 16 to 17 reported serious thoughts of taking their own lives.

To provide better surveillance for teenagers at risk of suicide, Coleman and his fellow researchers stress the importance of this study.

"Our findings support school- or community-wide interventions over strategies targeting those who personally knew the decedent, suggests that allocating resources following an event may be especially important during earlier adolescence, and implies that schools and communities should be aware of an increased risk for at least 2 years following a suicide event," said Coleman.

The results of this study were published in the Canadian Medical Association Journal.

Source: Swanson SA, Colman I. Association between exposure to suicide and suicidality outcomes in youth. Canadian Medical Association Journal. 2013.