Series Suicide 3 Means restriction for suicide prevention Paul S F Yip, Eric Caine, Saman Yousuf, Shu-Sen Chang, Kevin Chien-Chang Wu, Ying-Yeh Chen Limitation of access to lethal methods used for suicide—so-called means restriction—is an important population Lancet 2012; 379: 2393–99 strategy for suicide prevention. Many empirical studies have shown that such means restriction is eff ective. Although See Editorial page 2314 some individuals might seek other methods, many do not; when they do, the means chosen are less lethal and are See Comment page 2316 associated with fewer deaths than when more dangerous ones are available. We examine how the spread of This is the third in a Series information about suicide methods through formal and informal media potentially aff ects the choices that people of three papers about suicide make when attempting to kill themselves. We also discuss the challenges associated with implementation of means Department of Social Work and restriction and whether numbers of deaths by suicide are reduced. Social Administration (Prof P S F Yip PhD, S Yousuf FCPS) and Center for Introduction cannot be accessed with interventions or restrictions at Suicide Research and For more than a century, writers and researchers have the time of their greatest risk; indeed, they often seek Prevention (Prof P S F Yip, considered suicide from two opposite perspectives, to avoid detection. The probability of individuals S-S Chang PhD), University of invoking broad cultural and societal factors as causes or attempting suicide decreases when they are precluded Hong Kong, Hong Kong SAR, China; Center for the Study and 10 focusing on uniquely individual characteristics and experi- from implementing a preferred method —ie, suicide Prevention of Suicide, ences to explain why people kill themselves. Public health attempts are often method-specifi c. Moreover, if a Department of Psychiatry, approaches to suicide prevention, however, have to highly lethal method is not available and some University of Rochester, integrate these viewpoints and to develop strategies that individuals do not defer their attempt, they frequently Rochester, NY, USA (Prof E Caine MD); VA Center will benefi t most lives in an eff ective and measurable way. use less lethal, more common ones (eg, drug overdose). of Excellence for Suicide Suicide is a well recognised public health challenge. From the perspectives of public health and injury Prevention, Canandaigua, NY, WHO estimates that the global suicide rate is about prevention, the choice of a method that is less lethal USA (Prof E Caine); Department of Social Medicine, National 16 per 100 000 individuals per year, which is a 45% than are others can be advantageous if the attempt Taiwan University College of 1 increase in the past 45 years. Depending on the nation proves to be non-fatal. Medicine, Taipei, Taiwan cited by WHO, suicide is one of the top three leading The case fatality of suicide methods varies greatly (K C-C Wu PhD); Department of causes of death in people aged 10–24 years or 15–44 years, (appendix).11–14 The potentially fatal moments of suicidal Psychiatry, National Taiwan University Hospital, Taipei, and often is an especially large burden late in life, when crises are often brief. Strongly felt ambivalence is Taiwan (K C-C Wu); Taipei City 2 9 suicide rates are highest in many countries. Therefore, common, with competing wishes to die and to live. The Psychiatric Centre, Taipei City suicide causes the loss of many potential years of life and sudden, unplanned (or briefl y planned) nature of many Hospital, Taipei, Taiwan has substantial economic and emotional costs, disrupting suicides implies that individuals tend to use the method (Y-Y Chen ScD); and Institute of Public Health and Department families, communities, and society, broadly ramifying most readily accessible to them. When a lethal method is of Public Health, National 3 sadness and loss. unavailable at the moment of potential action, suicide Yang-Ming University, Taipei, Many countries have initiated suicide prevention attempts might be delayed so that (in some cases at least) Taiwan (Y-Y Chen) programmes,4,5 which use public health strategies that suicidal impulses will pass without fatal eff ects.15 Even Correspondence to: focus on individuals in known high-risk groups and when individuals have planned, poor access to the most Dr Ying-Yeh Chen, 309 Songde Road, XinYi District, promote population-oriented strategies to broadly reduce lethal means can be a substantial impediment. Taipei City 110, Taiwan risk, in keeping with Rose’s theorem (many people at low [email protected] risk might give rise to more cases than would a small number at high risk).6 Suicide is not a disease caused by Search strategy and selection criteria See Online for appendix well defi ned pathological mechanisms, and the occur- We searched PubMed, PsycINFO, ISI Web of Knowledge, and rence of suicidal behaviour is usually an outcome of The Cochrane Library, with the terms “suicide” in combination complex interactions of socio-environmental, behav- with each method (ie, “jumping”, “hanging”, “charcoal 6 ioural, and psychiatric factors. Identifi ed risk factors, burning”, “carbon monoxide poisoning”, “drowning”, such as severe depression or other mental illnesses, do “pesticide*”, “fi rearm*” and “medicine*” or “drug overdose”) not have suffi cient specifi city (ie, high rates of false and “restriction”, “availability”, “access”, or “means”. We 7 positives) to guide eff ective preventive actions. included reports of epidemiological studies showing change One important population strategy to reduce suicides in suicides or suicide rates after method restriction published has been modifi cation of the environment to decrease between January, 2001, and January, 2012. Review articles, general access to suicide means. This approach (so- case reports, or studies based on clinical populations or those called means restriction) is reported to be one of that had non-fatal outcomes (eg, suicidal behaviour or the intervention measures with strongest empirical ideation) were excluded. The reference lists of identifi ed 8,9 support. Several factors apparently underpin the reports were also examined for relevant references. eff ectiveness of this approach. Many suicidal people www.thelancet.com Vol 379 June 23, 2012 2393 Series Although means restriction is considered a generic forcing the use of a less lethal method. Because means preventive intervention, few investigators have assessed restriction is broadly applied, detection of its individual- the relative strength of supporting evidence for diff erent level eff ect is often impossible; it is best measured by methods. Moreover, the potential eff ect of decreased aggregate fi ndings of method-specifi c community rates access to various methods on overall suicide rates in of suicide and related self-harm injuries. diff erent countries or regions has not been established. As a public health measure, means restriction has a We review the empirical evidence for means restriction long history; removal of the pump handle in Broad Street, from the past decade (fi gure) and assess its eff ectiveness London, UK, by John Snow was an early example and a and its relation to the dissemination of information about historic landmark in public health practice.16 Similar diff erent methods of suicide through various media approaches have been widely applied in criminology, with outlets. We put special emphasis on the diffi culties the label of opportunity-reduction theory (or so-called encountered when attempts to measure potential sub- situational crime prevention).17 Instead of a focus on stitution eff ects are made. Additionally, we draw attention individual criminals, an opportunity-reduction approach to the potential of socially enacted means restriction introduces discreet managerial and environmental (ie, not absolute restriction) as a public health interven- changes to reduce the opportunities for crime. Suicide tion for commonly available products. can be aff ected or forestalled by alteration of environments or access.17 To be successful, this type of strategy depends Theory of means restriction on committed societal leadership and sustained political Suicide is a rare event and high-risk factors are common will. This approach fi ts with the notion of context changes (eg, depression, other mental disorders). A recurring to make individuals’ default decisions healthy. The challenge in suicide prevention is how to accurately principle of this type of intervention is that individuals identify vulnerable individuals in populations at risk. A would have to expend substantial eff ort not to benefi t.18 prevention strategy that targets the population as a whole, Although means restriction can be broadly applied, such as means restriction, has many advantages, especially related approaches exist for individuals. Clinicians can when implemented through so-called distal measures— work with high-risk patients and their kin to remove eg, removal of carbon monoxide from domestic gas or potentially lethal methods from the immediate environ- withdrawal of highly lethal pesticides from the market. ment. By contrast with universal approaches, this strategy Means restriction entails a community or societal necessitates care providers’ vigilance and cooperative action that (ideally) does not depend on an individual’s participation by people close to the suicidal individual. intention or volition. Applied to the population as a Such safety planning is not means specifi