Youth who had a schoolmate die by suicide are significantly more likely to consider or attempt suicide, according to a study in published in CMAJ (Canadian Medical Association Journal). This effect can last 2 years or more, which has implications for strategies following schoolmate suicides.
"We found that exposure to suicide predicts suicidality," writes senior author Dr. Ian Colman, Canada Research Chair in Mental Health Epidemiology and Assistant Professor, University of Ottawa, with lead author Sonja Swanson, from Harvard School of Public Health, Boston. "This was true for all age groups, although exposure to suicide increased the risk most dramatically in the youngest age group, when baseline suicidality was relatively low."
The concept that exposure to suicide can create suicidal thoughts or actions is called "suicide contagion."
Researchers looked at data from Statistics Canada's National Longitudinal Survey of Children and Youth on 22 064 children aged 12-17 years from across the country. They found that the suicide of a schoolmate magnifies the risk of suicidality for a young person, regardless of whether the young person personally knew the deceased. This risk was particularly strong among 12 to 13 year olds, who were 5 times more likely to have suicidal thoughts (suicide ideation) after exposure to a schoolmate's suicide than those who had had no exposure (15% v. 3%). In this age group, 7.5% attempted suicide after a schoolmate's suicide compared with 1.7% without exposure.
"Suicidality is of utmost public health concern, both as a predictor of suicide and because of its own burden on individuals and society," write the authors.
The apparent "suicide contagion" effect was less pronounced in older children, although 14 to 15 year olds exposed to suicide were still almost 3 times more likely to have suicidal thoughts, and 16 to 17 year olds were twice as likely.
"Perhaps any exposure to a peer's suicide is relevant, regardless of the proximity to the decedent," they write. "It may be best for postvention strategies to include all students rather than target close friends."
By ages 16-17 years, 24% of teens -- 1 in 4 -- had a schoolmate die by suicide, and 20% personally knew someone who died by suicide.
"Given that such exposure is not rare, and appears to be strongly related to suicidality outcomes, further understanding of this association has the potential to help in the prevention of a substantial proportion of adolescent suicidal behaviours," write the authors.
They conclude that broader, longer-lasting strategies are required. "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," the authors conclude.
In a related commentary, Dr. India Bohanna, School of Public Health, James Cook University, Cairns, Queensland, Australia, states that this study "provides convincing evidence that, among young people, exposure to suicide is a risk factor for future suicidal behaviour. This is extremely important because it tells us that everyone who is exposed to suicide should be considered when postvention strategies are developed."
Dr. Bohanna reiterates that strategies to limit the risk of suicide contagion are critical.
"The idea that suicide is contagious has always been controversial for various reasons; however, this important study should put many, if not all, doubts to rest. A unified and concerted effort now needs to be directed toward developing evidence-based postvention strategies. We need to know what works in mitigating the risk of contagion and why."