Lethality of Firearms Relative to Other Suicide Methods: a Population Based Study E D Shenassa, S N Catlin, S L Buka
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J Epidemiol Community Health: first published as 10.1136/jech.57.2.120 on 1 February 2003. Downloaded from 120 RESEARCH REPORT Lethality of firearms relative to other suicide methods: a population based study E D Shenassa, S N Catlin, S L Buka ............................................................................................................................. J Epidemiol Community Health 2003;57:120–124 Objectives: (1) To quantify lethality of firearms relative to other suicide methods, (2) to quantify the extent to which suicide mortality may be reduced by limiting access to firearms. Methods: Data on suicides and hospitalised para-suicides that occurred in the state of Illinois from 1990 to 1997 were combined. Total number of episodes for each suicide method was estimated as See end of article for the sum of the number of suicides and the number of para-suicides for that method. Gender and suicide authors’ affiliations method were used as proxies for intention to die, and estimated lethality of suicide methods within ....................... method-gender groups (for example, male firearm users). Logistic regression was used to quantify the Correspondence to: lethality of firearms relative to other suicide methods. Excess mortality associated with the use of fire- Dr E D Shenassa, Centers arms was estimated by conservatively assuming that in the absence of firearms the next most lethal for Behavioral and suicide method would be used. Preventive Medicine, One Results: From January 1990 to December 1997, among individuals 10 years or older in the state of Hoppin Street, Suite 500, Illinois, there were 37 352 hospital admissions for para-suicide and 10 287 completed suicides. Fire- Providence, RI 02903, USA; arms are the most lethal suicide method. Episodes involving firearms are 2.6 times (95% CI 2.1 to 3.1) Edmond_Shenassa@ more lethal than those involving suffocation—the second most lethal suicide method. Preventing access Brown.edu to firearms can reduce the proportion of fatal firearms related suicides by 32% among minors, and Accepted for publication 6.5% among adults. 27 June 2002 Conclusions: Limiting access to firearms is a potentially effective means of reducing suicide ....................... mortality. uicide prevention efforts date back at least to pre- lethal and irreversible suicide methods is a population level Christian times, when Roman emperors made laws to reduction in suicide mortality (not attempts). The primary Scurb the practice of tax evasion through suicide.1 Modern aim of this study is to quantify the reduction in suicide mor- efforts include suicide awareness and prevention programmes tality that may result as a consequence of limiting access to that aim to identify and treat suicidal individuals. Some of firearms. these targeted programmes have been effective in identifying While previous studies have estimated the risk of suicide those at risk for suicide.2 For example, from 1991–97 during associated with the availability of firearms,23–31 there are no National Depression Screening Day, 316 700 people were epidemiological studies that quantify the lethality of firearms http://jech.bmj.com/ screened for risk of suicide and provided referrals if needed.3 relative to other suicide methods. This may be attributable in However, other efforts have not proved as effective.4–6 Many part to the difficulties inherent in collecting data on reasons exist for programmes’ lack of success; one pervasive para-suicides (that is, suicide attempts), without which any problem is the difficulties inherent in identifying and reaching estimate of lethality would be biased. (This bias, which people who are at risk for suicide.7 For example, although one emanates from sociological and psychological distinctions third of suicide victims visit a physician shortly before they between para-suicides and suicides, will be considered below.) die, most do not divulge their suicidal intent or even their Here we greatly, but not completely, reduce this source of bias 8–11 depressed mood. It seems that many, if not most, suicidal by combining data on hospital admissions for para-suicides on September 26, 2021 by guest. Protected copyright. people are first noticed by mental health professionals only with data on completed suicides. The specific aims of this after a suicide attempt. For these people, surviving a suicide study are: (1) to quantify lethality of firearms relative to other attempt presents their best chance of receiving appropriate suicide methods, (2) to quantify the extent to which suicide care. Given the difficulties in identifying suicidal individuals, mortality may be reduced by limiting access to firearms. universal preventive efforts aimed at the entire community deserve serious consideration.12 13 One such universal approach is to limit access to substances METHODS and products that are likely to be misused by suicidal Two sources of data, spanning the years 1990 to 1997, were individuals. The Arsenic Act of 1851 is an early example of this used in the analysis presented below: data on completed sui- approach.14 More recent examples include reductions in the cides were compiled from annual mortality data files of the carbon monoxide content of domestic gas,15 16 development of Chicago Department of Public Health; these files contain less toxic antidepressants,17 and restrictions in the prescription sterilised records abstracted from death certificates. Data on of potentially lethal drugs.18 19 In some instances reduced para-suicides were abstracted from administrative hospital availability of certain lethal substances was accompanied by discharge data compiled as part of an Illinois State contemporaneous reductions in the suicide rates,20 21 in other mandate.32 These files contain information from acute care instances similar reductions in the availability of lethal facilities that were operating in the state of Illinois between substances were not accompanied by reduced suicide rates.22 1990 and 1997, but they do not include data from Veteran’s Whereas it remains uncertain whether universal approaches Administration hospitals, nor from psychiatric hospitals. Sui- to suicide prevention can actually prevent suicide on a large cides and para-suicides were identified by International scale, it is likely that a consequence of limiting access to very Classification of Diseases external causes of injury codes: www.jech.com J Epidemiol Community Health: first published as 10.1136/jech.57.2.120 on 1 February 2003. Downloaded from Lethality of guns compared with other suicide methods 121 Table 1 Distribution of suicide and hospitalised para-suicide episodes - Illinois 1990–1997 Complete sample Male Female Minor Below 18 Adult 18 and over % of total* % of total* % of total* % of total* % of total* Suicide method (n) % fatal† % fatal† % fatal† % fatal† % fatal† Poisons‡ (35476) 74.5 58.8 87.8 84.7 73.0 6.5 11.1 3.9 0.9 7.4 Firearms (5043) 10.6 20.2 2.3 3.9 11.5 96.5 96.5 96.0 95.3 96.5 Suffocation§ (2574) 5.4 9.6 1.8 2.7 5.8 90.4 90.7 89.0 65.2 92.0 Cuts¶ (2409) 5.1 6.1 4.1 4.8 5.1 6.7 9.9 2.6 0.7 7.5 Crash/jump** (676) 1.4 2.2 0.8 0.5 1.6 74.0 76.1 68.8 51.7 75.0 Exposure†† (183) 0.4 0.5 0.3 0.3 0.4 56.3 64.0 43.5 6.7 60.7 Other‡‡ (1278) 2.7 2.5 2.9 3.1 2.6 1.8 2.4 1.4 0.5 2.0 Total episodes 47639 21965 25674 5943 41696 Total fatal episodes 10287 8222 2065 394 9893 *Percentage of all episodes coded with the particular suicide method (for example, 74% of all episodes where with poisons). †Percentage of completed suicides from each suicide method (for example, 7% of episodes involving poisons were lethal). ‡Episodes involving prescription drugs, over the counter drugs and toxic substances such as gasoline and household cleaning substances. §Episodes involving hanging, strangulation, and suffocation. ¶Episodes involving cutting or piercing instruments. **Episodes involving crash into a moving object or jump from a high place. ††Episodes involving electrocution or exposure to heat or cold. ‡‡Episodes involving all other methods, includes episodes involving unknown methods and multiple methods (for example, firearms and poisons). E950-E959,33 and were classified into seven categories accord- among firearm users is more similar than between firearm ing to suicide method(s). users and those taking pills. Thus, grouping people by their To reduce the possibility of double counting an episode, it suicide method can partially control for their intention to die. was assumed that hospitalisation episodes that culminated in Moreover, because there are stable gender differences in death also appeared as fatal episodes in the annual mortality intention to die,37 grouping by gender should also partially files. Therefore, 183 hospital admissions that culminated in control for the effect of intention to die. Thus, for the current death were excluded from the analyses. These excluded analysis, we make the simplifying assumption that intention episodes were similar to the 10 287 completed suicides that to die is relatively similar among groups of same gender indi- appeared in the annual mortality files. Compared with admis- viduals who used the same suicide method. For example, male sions that did not culminate in death, these fatal episodes firearm users constitute one such method gender group with were significantly more likely to involve males and older relatively homogenous intention to die. Female firearm users people (47 versus 31 years). Also, to reduce the bias associated constitute another method gender group with relatively with potential misdiagnosis of suicide as accident, we homogenous intention to die. included in the study only episodes involving those ages 10 or Within each method gender group, however, the reported http://jech.bmj.com/ older.34 age related differences in suicide mortality34 should remain.