Brisbane Lord Mayor Graham Quirk’s recent announcement that barriers are to be erected on the Story Bridge in an effort to reduce suicides is very welcome. Studies consistently show that barriers have a high likelihood of reducing the number of suicides at a particular location, making them a useful and successful tool for tackling iconic suicide “hot spots”.
But the impacts of barriers on suicides at one location are not representative of what we can expect of means restriction (limiting access to methods of suicide) more generally, as a suicide prevention measure.
In fact, research into barriers and suicide can create an artificial and overly optimistic impression of the efficacy of means restriction.
Reducing access to lethal means
Means restriction may seem a simple way of preventing suicides. It includes measures such as erecting safety barriers on bridges, detoxifying domestic gas, and restricting access to firearms, poisons and drugs. It can be enacted through legislation, making it politically appealing.
However, society, culture, and context matter. Means restriction can be very effective, but it can also have quite different impacts across different locations and populations. Sometimes impacts may only be short term, rather than long-lasting. And what works to reduce suicides for one group or in one location may not work for another.
Measures to prevent suicide through means restriction must be evidence-based and designed to reach vulnerable people who are most at risk of suicide. They must also be integrated with a wide range of other suicide-prevention measures.
Importantly, means restriction is most likely to be effective in reducing overall suicide rates when it targets commonly used, highly lethal methods that account for a high percentage of suicide deaths overall.
But if the majority of suicides in a particular group or location involve methods that cannot be easily curtailed, means restriction is not likely to deliver any real changes in suicide numbers. Unfortunately, in Australia, the method that accounts for the highest percentage of suicides is hanging – a highly lethal method that is almost impossible to restrict. This highlights the importance of early identification and intervention, before an at-risk individual reaches a crisis point.
So if means restriction has the potential to reduce suicides using one method, will people just shift to another method?
One on hand, some suggest that if substitution happens, then restricting highly lethal methods may still reduce deaths. When substitution occurs, it may involve less lethal methods, increasing the chances of survival.
On the other hand, if a method with relatively low lethality is restricted, then it is possible that people who may have used that method will instead use a more lethal means, resulting in a lower likelihood of survival.
But the extent to which method substitution occurs, following means restriction, remains a topic of considerable debate. Different studies on means restriction have produced inconsistent findings. Some show that suicides using alternative methods rise substantially after means restriction, while others find little or no evidence that any substitution took place.
Also, the likelihood of substitution seems to vary across different groups and contexts. For instance, women seem more responsive to means restriction, while men appear more likely to substitute other methods.
So does means restriction save individual lives?
This question is perhaps the hardest to answer. Although it is possible to assess changes in suicide rates by particular methods for populations (such as the Australian population overall, or men, or young people), it is far more difficult to show this at the individual level.
To do this, we would need to know the numbers of people who were restricted from accessing one method of suicide who did, and did not, die by some other method of suicide.
Population-level data does not tell us this. All it tells us is whether deaths by particular methods change overall. This is useful information for policy evaluations, but it means we must be cautious not to conclude that specific lives that would otherwise have been lost, have necessarily been saved.
Population-level data also has its limits. Usually, other interventions occur alongside means restriction. Improved treatment for mental illnesses and reductions in risk factors for suicide, for example, also influence declines in suicide rates. Using a range of evidence-based interventions is good practice, but also makes it hard to distinguish the effects, or for that matter the cost-effectiveness, of each specific intervention.
Ultimately, if we are to strive for the best possible suicide prevention strategies, we need to recognise that the apparently simple measure of means restriction is far more complex than it may first seem. And perhaps most importantly, we must also keep trying to better understand what happens in the lives of those individuals that means restriction does not save.
If you or someone you know needs help, contact Lifeline’s 24-hour helpline on 13 11 14, SANE Australia on 1800 18 7263 or the Beyondblue Info Line on 1300 22 4636.