Around the world, certain places have gained notoriety as suicide hotspots. These places are often heights, such as bridges or cliffs, from which suicide by jumping is common.

Although not a major contributor to overall suicide rates, suicides by jumping are of particular concern due to their ability to cause distress or physical harm to bystanders, and due to the method’s high fatality rate. Because of this, structural interventions, such as barriers, are often installed or considered at jumping hotspots in order to attempt to physically prevent suicide attempts. Such interventions are often costly to build, and so proposed installation can be met with opposition, especially as there is a lack of clear information on the effectiveness of structural interventions in actually preventing suicides.

A recent meta-analysis tackled this question of whether structural interventions reduced suicide rates, by comparing suicides by jumping from various hotspots before and after interventions were installed. The study also approached the main criticism of structural interventions, namely that installation merely shifts jumping suicides from one site to another, with no overall reduction in suicide rates by jumping.

Methods

Having searched through some databases and reference lists, the authors initially identified 194 articles on the research topic. To be included in the meta-analysis, studies needed to focus on the installation of structural interventions in preventing suicide and contain death rate data for both before and after the installation of interventions. Removing studies not meeting these criteria, duplicates and non-research papers left 11 articles in the meta-analysis, corresponding to only 9 research studies. These studies related to varied interventions, including putting barriers on bridges, installing safety nets or restricting road access to cliffs.

Using the number of suicides by jumping before structural intervention, an ‘expected’ number of suicides was calculated for the period after intervention. This was then compared to actual numbers of suicides for the post-installation period, giving a risk ratio related to the installation of structural interventions. A similar process was followed for jumping sites other than the hotspots, if a study included such information.

Results

For jumping hotspots:

• Pre-structural intervention there was an average of 5.7 deaths per year. Following structural intervention, this fell to an average of 0.5 deaths per year.
• The installation of structural interventions led to 86% fewer suicides than otherwise would have been expected – structural intervention was associated with a risk ratio of 0.14 (95% CI [0.09 to 0.21])

At surrounding jump sites:

• Before structural intervention, there was an average of 2.8 deaths per year. This rose to an average of 3.6 deaths per year, following intervention.
• Structural intervention seemed to increase suicides by 44% greater than would have been expected – a risk ratio of 1.44 (95% CI [1.15 to 1.81]).

Although jumping suicides do appear to have increased at sites without structural interventions, over all jump sites, the numbers of suicides were found to decrease by an average of 28% per year from expected rates, following intervention at hotspots.

Conclusions

The authors conclude that:

Structural interventions at ‘hotspots’ avert suicide at these sites. Some increases in suicide are evident at neighbouring sites, but there is an overall gain in terms of a reduction in all suicides by jumping.

Limitations

Although the conclusions drawn are supported by the data available in the paper, there are limitations of the analysis that should be considered:

• The meta-analysis only included data from 8 hotspots – such a limited sample of sites may not show clearly the effects on suicide rates following intervention. A more exhaustive literature search may have found more data, though suitable studies are likely to be limited.
• The interventions included in the meta-analysis are very different. Some of the interventions were ‘accidental’ – reduced access in both studies focusing on cliffs arose from coincidental road closures. Deliberate interventions also varied with installed barriers on bridges varying in height from 2 metres to 5 metres. Some of the structural interventions were also installed alongside other interventions, such as telephone crisis lines. This variability in the intervention undertaken at the various sites limits the usefulness of the study as observed affects on suicide rates may have arisen from many different sources.
• Jumping suicides, even at ‘hotspots’, are relatively rare and so sample sizes may be too small to give a clear picture of any effects of intervention.
• The study is not useful in determining whether there is an overall reduction in suicides as no general suicide rate data is provided – this could mean the suicides have just ‘shifted’ to other methods.

If you need help

If you need help and support now and you live in the UK or the Republic of Ireland, please call the Samaritans on 116 123.

If you live elsewhere, we recommend finding a local Crisis Centre on the IASP website.

We also highly recommend that you visit the Connecting with People: Staying Safe resource.

Link

Pirkis J, Spittal MJ, Cox G, Robinson J, Cheung YT, Studdert D. The effectiveness of structural interventions at suicide hotspots: a meta-analysis. BMC Public Health 2013, 13:214 doi:10.1186/1471-2458-13-214