Reducing a Suicidal Person’s Access to Lethal Means of Suicide: A Research Agenda

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Reducing the availability of highly lethal and commonly used suicide methods has been associated with declines in suicide rates of as much as 30%–50% in other countries. The theory and evidence underlying means restriction is outlined. Most evidence of its efficacy comes from population-level interventions and natural experiments. In the U.S., where 51% of suicides are completed with firearms and household firearm ownership is common and likely to remain so, reducing a suicidal person’s access to firearms will usually be accomplished not by fiat or other legislative initiative but rather by appealing to individual decision, for example, by counseling at-risk people and their families to temporarily store household firearms away from home or otherwise making household firearms inaccessible to the at-risk person until they have recovered. Providers, gatekeepers, and gun owner groups are important partners in this work. Research is needed in a number of areas: communications research to identify effective messages and messengers for “lethal means counseling,” clinical trials to identify effective interventions, translational research to ensure broad uptake of these interventions across clinical and community settings, and foundational research to better understand method choice and substitution. Approaches to suicide methods other than firearms are discussed. Means restriction is one of the few empirically based strategies to substantially reduce the number of suicide deaths.

Introduction

The National Action Alliance for Suicide Prevention established the Research Prioritization Task Force in 2010 to identify interventions capable of reducing the suicide rate by 20% over a 5-year period. Twelve goals emerged. We discuss the 12th: “reduce access to lethal means that people use to attempt suicide” (briefly, means restriction or means reduction).

A suicidal person’s access to highly lethal means, or methods, of suicide can be reduced through (1) physically impeding access (e.g., using gun locks and bridge barriers); (2) reducing the lethality or toxicity of a given method (e.g., reducing carbon monoxide [CO] content of motor vehicle exhaust); or (3) reducing “cognitive access,”1 that is, reducing a particular method’s appeal or cognitive salience (e.g., discouraging media coverage of an emerging suicide method). We focus here largely on the first two approaches.

Reducing access to lethal means saves lives when people who cannot readily obtain a highly lethal method either attempt with a method less likely to prove fatal or do not attempt at all (Figure 1). The rationale rests on four well-established observations. First, many suicidal crises are short-lived. A survey of people who had seriously considered suicide in the past year found that for about 30%, the suicidal period lasted under an hour.2 Surveys of attempters have found that the interval between deciding on suicide and actually attempting was 10 minutes or less for 24%–74% of attempters (with the lower end of the range reported by a study of those nearly dying in their attempt).3, 4, 5

Second, the method people use in suicidal acts depends, to a non-trivial extent, on its ready availability.6, 7 Third, the proportion of attempts that result in death (case fatality ratio) varies dramatically across methods, ranging from a high of 85%–90% for firearms to a low of 1%–2% for the methods most commonly used in attempts—medication overdoses and sharp instrument wounds.8 The lethality of the method readily available during a suicidal crisis therefore plays an important role in whether the person survives an attempt; intent matters, but means also matter.

Fourth, approximately 90% of attempters who survive a nonfatal attempt will not go on to die by suicide thereafter,9 a finding that holds true even in studies focusing only on medically serious attempts, such as jumping in front of a train.10 Therefore, helping people survive periods of acute suicidal risk by reducing their access to highly lethal methods is likely to help many people survive in both the short and long term.

Reducing access to lethal means saves lives if the methods available for substitution, on balance, are less likely to prove lethal. Firearms account for more than half of suicides in the U.S. and have the highest case fatality ratio. A number of factors are theorized to influence the lethality of a given method. The first is inherent deadliness. For example, car exhaust with a high CO level will be more deadly than car exhaust with a low CO level. The second is ease of use. A method that requires technical knowledge is less accessible than one that does not.

The third is accessibility. Given the brief duration of some suicidal crises, a lethal dose of pills in the nightstand poses a greater danger than a prescription that must be hoarded over months to accumulate a lethal dose. Similarly, a gun in the closet poses a greater risk than a very high bridge 5 miles away, even if both methods have equal lethality if used. The fourth is ability to abort mid-attempt. More people start an attempt and abort it than carry it through2; therefore, methods that can be interrupted without harm mid-attempt—such as overdose, cutting, CO poisoning, and hanging/suffocation—offer a window of opportunity for rescue or change of heart that guns and jumps do not. The fifth factor is acceptability to the attempter. Although fire, for example, is universally accessible, it is rarely used in the U.S. for suicide.

At the population level, no measurable impact of means restriction on overall suicide rates is likely to be observed (even if, on balance, lives are saved) if the restricted method constitutes a very small proportion of all suicides or if the restricted method is of low lethality. If all sharp instruments magically disappeared, for example, in spite of their frequent use in suicide attempts there would be little measurable impact on suicide deaths, given their low case fatality ratio (sharps constitute only 2% of suicide deaths). Importantly, a possible, though unsubstantiated, unintended impact of reducing access to popular low-lethality methods may be an increase in suicide risk if attempters substitute more lethal methods.

Section snippets

Population-Level Natural Experiments

Before 1960, the leading suicide method in the United Kingdom was inhalation of domestic gas. Following discovery of a cheaper, nontoxic source of natural gas in the North Sea, gas suicides fell to nearly zero. Suicides by other methods increased somewhat, but, importantly, the net result was a drop of approximately 30% in the overall suicide rate.11, 12 These findings held in other countries where domestic gas was a leading method,13, 14 but not in those where gas accounted for a small

Firearms and Suicide in the U.S.

In the U.S., more suicides are completed with a firearm than by all other methods combined. About one in three homes contain firearms and 51% of all suicides involve firearms.34 Miller et al.34 have provided a review of U.S. firearm suicides. All U.S. case-control studies that have examined the issue35, 36, 37, 38, 39 have found that the risk of suicide is two- to five-fold higher in gun-owning homes for all household members, with relative risk being especially high for youth and people

Applying the Lessons of Means Restriction to the U.S.

Suicide rates can be substantially reduced—without necessarily changing underlying mental illness or suicidal behavior—by making it more difficult to die in an act of deliberate self-harm. Despite evidence across studies (including targeted interventions, natural experiments, case control, cohort, and ecologic studies) of its potential to save lives, means restriction historically has not been prioritized in the U.S.

One reason may be the misperception that reducing access requires embracing gun

Research Needs

The body of evidence on means reduction comes from studies examining changes in exposure to suicide methods resulting from natural experiments and interventions at the population level. Individual-level interventions are far more complex. They require identifying at-risk groups, learning the right messages to deliver, finding the right messengers to deliver them, and learning how to change behavior—not insignificant challenges. They also require changing practice among providers,

Changing the Paradigm

Currently, the suicide prevention field focuses on identifying people at risk and getting them into treatment. A challenge facing the field is to shift the paradigm such that researchers, practitioners, patients, and the broader population understand that reducing a suicidal person’s access to lethal means also has important life-saving potential. A first step is educating researchers and practitioners during training and continuing education about the evidence base.

Reducing the availability of

Acknowledgments

Publication of this article was supported by the Centers for Disease Control and Prevention, the National Institutes of Health Office of Behavioral and Social Sciences, and the National Institutes of Health Office of Disease Prevention. This support was provided as part of the National Institute of Mental Health-staffed Research Prioritization Task Force of the National Action Alliance for Suicide Prevention.

This work was funded with support from the Joyce Foundation and Bohnett Foundation.

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