Installation of a Bridge Barrier as a Suicide Prevention Strategy in Montréal, Québec, Canada

摘要

Objectives. We investigated whether the installation of a suicide prevention barrier on Jacques-Cartier Bridge led to displacement of suicides to other jumping sites on Montréal Island and Montérégie, Québec, the 2 regions it connects. Methods. Suicides on Montréal Island and Montérégie were extracted from chief coroners’ records. We used Poisson regression to assess changes in annual suicide rates by jumping from Jacques-Cartier Bridge and from other bridges and other sites and by other methods before (1990–June 2004) and after (2005–2009) installation of the barrier. Results. Suicide rates by jumping from Jacques-Cartier Bridge decreased after installation of the barrier (incidence rate ratio [IRR]?=?0.24; 95% confidence interval [CI]?=?0.13, 0.43), which persisted when all bridges (IRR?=?0.39; 95% CI?=?0.27, 0.55) and all jumping sites (IRR?=?0.66; 95% CI?=?0.54, 0.80) in the regions were considered. Conclusions. Little or no displacement to other jumping sites may occur after installation of a barrier at an iconic site such as Jacques-Cartier Bridge. A barrier’s design is important to its effectiveness and should be considered for new bridges with the potential to become symbolic suicide sites. Physical availability and sociocultural acceptability are important considerations in the choice of method of suicide. 1 Restricting access to commonly used methods of suicide is widely recognized as a suicide prevention strategy. Several studies have indicated that detoxification of domestic gas; mandatory use of catalytic converters in motor vehicles; restrictions on pesticides, barbiturates, and analgesics; use of lower toxicity antidepressants; firearm control legislation; and construction of barriers at jumping sites have been effective in reducing suicides by those methods. 1 However, evidence for the success of some of these strategies remains equivocal (e.g., use of catalytic converters in Australia, 2 reduction of paracetamol pack size in the United Kingdom 3,4 ). Furthermore, restricting one method can result in substitution with another, although substitution may depend on the popularity of the method and the availability of alternative methods that are acceptable to the individual. 5–7 A change in overall suicide rates may be obscured if method substitution occurs or if the restricted suicide method accounts for a relatively small proportion of all suicides. 1,8 For suicide by jumping, displacement to other jumping sites is probably more likely than a change in method. Two studies found no shift to other jumping sites after installation of barriers, but they did not examine the effect on overall suicide rates. 9,10 By contrast, other studies have shown evidence of displacement, with overall suicide rates remaining unchanged. 11–13 In 1 of these latter studies, jumping suicides from other bridges and buildings in Toronto increased after the construction of a suicide barrier at Bloor Street Viaduct. 13 The researchers suggested that the viaduct was not a uniquely attractive location for suicide and was therefore interchangeable with other sites. By contrast, some jumping sites are reportedly the only site a suicidal individual would consider (e.g., Golden Gate Bridge, Eiffel Tower, Empire State Building); their status as suicide magnets is enhanced by the ease of access, perceived lethality of the jump, notoriety as a popular suicide site, romantic view of death they encourage, media attention, and unique features such as being over water. 10,13–16 All of these factors existed for Jacques-Cartier Bridge, which spans the St. Lawrence River between Montréal Island and Montérégie, Québec, with an average of 10 suicides annually before the construction of a barrier in 2004 (P-A?Perron, unpublished data, 2002). To create the barrier, the existing 1.1-meter steel palisade fencing was extended a further 1.4 meters and curved inwardly at the top, making it high and difficult to climb (see image available as a supplement to the online version of this article at http://www.ajph.org ). An initiative to have a barrier installed was unsuccessful in 1996 and almost halted in 2002 because of the argument that a barrier would not decrease suicides but merely displace them to other sites. To test the validity of this argument, we assessed whether displacement to other jumping sites on Montréal Island and Montérégie occurred.