Firearms and Violence A Critical Review (2005) / Chapter Skim
Currently Skimming:
7 Firearms and Suicide
7 Firearms and Suicide
Pages 152-200
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 152... ...
A large body of literature links the availability of firearms to the fraction of suicides committed with a gun. Yet, a central policy question is whether changes in the availability of firearms lead to changes in the overall risk of suicide.
|
From page 153... ...
In this case, if substitutes were easily enough available, gun access restrictions might reduce the incidence of gun suicide yet have no effect on the overall risk of suicide. Two examples highlight this possibility: · Reverse Causality: The risk of suicide might increase or decrease the like lihood of gun ownership.
|
From page 154... ...
Cross-Sectional Associations Almost all ecological studies using cross-sectional data, both within the United States and across countries, have found that both gun suicide rates and the fraction of suicides committed with a gun are higher in geographic areas with a higher prevalence of household gun ownership. This association has been reported by investigators across the spectrum of the gun control debate.
|
From page 155... ...
(2002a) do not incorporate control variables; they find a positive association between gun ownership and overall suicide rates in all age groups (incidence rate ratio 1.14; 95% CI 1.01-1.24)
|
From page 156... ...
handgun ownership) Miller et al.
|
From page 157... ...
FIREARMS AND SUICIDE 157 Results: Results: Results: Guns and Guns and Guns and Control Gun Nongun Overall Variables Suicides Suicides Suicides None all ages + 10-19: + all ages + 20-69: 0 70+: Major + + depression, suicidal thoughts, and urbanization, OR education, OR unemployment, OR alcohol consumption Poverty, + 0 + education, urbanization Poverty, + BRFSS:+ + urbanization Others: 0 None all ages + <45: 0 all ages + 45+: Divorce, 15-24: + 0 15-24: + education, 25-44: 0 25-64:0 unemployment, 45-84: + 65+: + urbanization None + n/a n/a continued
|
From page 158... ...
Australian gun ownership states Lester 9 regions Survey (1988b) 1970 Proxy: gun laws Lester 48 states Proxies: gun (1987a)
|
From page 159... ...
FIREARMS AND SUICIDE 159 Results: Results: Results: Guns and Guns and Guns and Control Gun Nongun Overall Variables Suicides Suicides Suicides None + Male:- n/a Female: 0 Community traits: + 0 OLS: + race, sex, age IV: 0 unemployment rate, poverty, income, home ownership, college enrollment, transience, population change, divorce, place of worship, etc. None + 0 None + 0 + None 0 0 % black, median + 0 0 age, % urban, divorce rate None + UFDR: 0 Other: 0 State, year fixed 0 0 0 effects continued
|
From page 160... ...
BRFSS = Behavioral Risk Factor Surveillance System; GSS = General Social Survey; FS/S = ratio of firearm suicide/total suicides; Cook Index = mean of firearm suicide/total suicide and firearm homicide/total homicide; HICRC = Harvard Injury Control Research Center; UFDR for an omitted variable, because any plausible causal effect of gun ownership should be independent of, or negatively associated with, the nongun suicide rate. There are several other possible explanations for Duggan's results; most obviously, it may be that Guns & Ammo subscribers are not representative of all gun owners; his arguments about confounding would also have been strengthened by the inclusion of some observable covariates.
|
From page 161... ...
studies, the existing cross-national surveys have looked for an association between rates of household gun ownership, overall suicide rates, and the fraction of suicides committed with a gun. And, like the U.S.
|
From page 162... ...
Four studies have attempted to link this change in the fraction of gun suicides with changes in gun ownership across time. Three of these four studies have found positive associations between proxies for gun ownership and the fraction of suicides committed with a gun, but only one study, focusing on youth suicide, found an association between gun ownership and overall suicide rates.
|
From page 163... ...
In particular, gun suicide rates are strongly correlated with gun prevalence across space and possibly across time, in the United States and across countries. Likewise, many ecological studies do report a cross-sectional association between gun ownership rates and overall suicide rates in the United States.
|
From page 164... ...
states, lower levels of mutual trust and civic engagement, as reported on the General Social Survey and on the Needham Lifestyle Survey, were associated with a higher fraction of suicides committed with a gun. This study did not examine the association between social capital, firearm ownership, and overall suicide rates.
|
From page 165... ...
Their basic results using the GSS and other ownership surveys are displayed in Table 7-2. The fraction of suicides committed with a firearm has the highest correlation among all of the measures considered, ranging from 0.81 in the state level data to 0.93 when using ownership data from the nine census regions.
|
From page 166... ...
. A similar problem is presented in Figure 7-1, which displays the relationship between FS/S and household gun ownership by age and gender.
|
From page 167... ...
in the US by age and sex. This figure shows that the relationship between FS/S and household gun ownership (as reported in the GSS)
|
From page 168... ...
do not consider issues associated with the statistical error of the model. Suppose instead that we consider another linear model, in which the gun suicide rate is a function of the gun ownership prevalence: FS/S = g0 + g1PREV + V, with V being a mean zero unobserved random variable, conditional on PREV (see, for example, Duggan, 2003)
|
From page 169... ...
. In particular, we find a negative association between the suicide rate and FS/S: in this simulation, if FS/S is a good proxy for ownership, gun owners are less likely than nonowners to commit suicide.
|
From page 170... ...
The geographical level of aggregation in state-level or regional ecological studies may be so high that there is no way of knowing whether the gun homicides or gun suicides occurred in the same areas with high levels of gun ownership. Thus, even if FS/S is found to be a valid proxy for state-level gun prevalence, something that is not yet established, ecological studies may lead to biased inferences.
|
From page 171... ...
For example, although suicide is the most common cause of firearm-related deaths in the United States, the overall suicide rate is approximately 11 suicides per 100,000 persons per year. Very few prospectively collected data sets would be large enough to draw precise inferences about completed suicide.
|
From page 172... ...
Furthermore, relatives may follow a "stopping rule": once the family has found a "sufficient" explanation for the occurrence of the suicide-whether it is a gun in the home or psychopathology -- they may be less likely to admit the presence of other, less socially acceptable risk factors; such ascertainment bias can lead to the underreporting of co-morbidity among risk factors and could explain reports of a greater frequency of gun ownership among suicides with no reported history of psychopathology. In the case of gun suicides, ascertainment bias may also arise because the outcome itself provides evidence of access to a gun.
|
From page 173... ...
All of the studies that the committee reviewed have found a positive association between household gun ownership and suicide risk, although the magnitude of the estimated association varies. Although more recent studies have used better data collection strategies and more appropriate study samples (e.g., Conwell et al., 2002; Beautrais et al., 1996)
|
From page 174... ...
gun suicides controls N = 36 n = 36 Brent et al. Adolescent Community (1999)
|
From page 175... ...
Firearm in Psychiatric diagnosis, +: any gun, handgun the home family history, stressful 0: not long gun life events, past treatment Matching: age, sex, county of origin, socioeconomic status continued
|
From page 176... ...
suicides with controls with substance substance abuse abuse N = 23a n = 12 Brent et al. Adolescent Community (1993a)
|
From page 177... ...
FIREARMS AND SUICIDE 177 Result: Gun Gun Covariates, Matching Access and Overall Measure Factors Suicide Risk Firearm in Psychiatric diagnosis, +: any gun, handgun the home family history, stressful 0: not long gun life events, past treatment 0: not gun storage Matching: age, race, sex, socioeconomic status, county of residence Firearm in Psychiatric diagnosis +: any gun, the home handgun Matching: age, sex, socioeconomic status, ·particularly when county of origin no psychiatric disorder is present Firearm in Psychiatric diagnosis, +: any gun, loaded the home family history, stressful gun life events ·particularly when Matching: age, sex, county no psychiatric of origin, socioeconomic disorder is present status Firearm in Alcohol use, illicit drug +: any gun the home use, domestic violence, living alone, education, ·particularly when previous hospitalization no psychopathology due to alcohol, current is reported psychiatric medication. Matching: age, race, sex, neighborhood Firearm in Psychiatric diagnosis, +: any gun the home family history; female headed household, treatment 0: Not gun storage history Matching: age, sex, county of origin Firearm in Precipitants, psychiatric +: any gun the home diagnosis, family history, exposure to suicidal contact bOverlapping samples, King County, Washington, and Shelby County, Tennessee.
|
From page 178... ...
Guns were a stronger risk factor for suicide among the 63 case subjects with no history of depression or mental illness (odds ratio 32.8; 95 percent confidence interval 4.6 to 232.8)
|
From page 179... ...
This implies that about 50 percent of out-of-home victims owned firearms, and that 60 percent of all victims owned firearms. Under these assumptions, the unmatched odds ratio comparing total suicides with control group equals 2.16 = (60/40)
|
From page 180... ...
. Like Kellerman and his colleagues, this research group found an association between family gun ownership and the risk of suicide, with an odds ratio of 3.0 (with a 95 percent confidence interval = 1.3-6.8)
|
From page 181... ...
For each case and control subject, family members were identified, and computerized records of handgun purchasers in Washington State were searched for the first occurrence of a handgun purchase from 1940 until the case's date of death. About 52.7 percent of the suicides were committed with a gun; 24.6 percent of persons who committed suicide had a history of a handgun purchase by themselves or a family member, compared with 15.1 percent of controls, with an adjusted relative risk of 1.9 (95 percent confidence interval 1.4 to 2.5)
|
From page 182... ...
This study did not investigate the risk of suicide among the family members of gun purchasers, but the changes in suicide risk over time were presented in more detail. Age and sex-standardized mortality ratios for handgun purchasers were compared with the mortality of the general adult population of California.
|
From page 183... ...
studies have consistently found that household gun ownership is associated with a higher overall risk of suicide, but the estimate of such an association was significantly smaller in a study from New Zealand. Although reverse causality cannot explain the association between guns and risk of suicide for adolescents, it remains possible that some other heritable or environmental family trait links the likelihood of gun ownership and suicide.
|
From page 184... ...
In general, laws restricting the buying and selling of firearms have been associated with lower rates of firearm suicide, but laws governing the right to carry firearms seem to have no association. Lower gun suicide rates have sometimes been associated with higher nongun suicide rates, and the findings regarding overall suicide rates have been less consistent: 5 out of 11 studies found an association between stricter gun laws and overall rates of suicide, another 5 studies found no significant association, and 1 study produced mixed results.
|
From page 185... ...
This study has been prominently cited as showing a significant decline in gun suicides following the institution of a ban on handguns. However, overall suicides, not gun suicides, are the policy question of interest, and the investigators did not report whether there were significant differences in the estimates of the trend in overall suicide rates.
|
From page 186... ...
DC gun laws 1985 Lester 9 regions, Strictness of (1988c) 1970 handgun control laws Lester 48 states, Strictness of (1987a)
|
From page 187... ...
FIREARMS AND SUICIDE 187 Results Results: Results: Gun Nongun Overall Controls and Strata Suicide Suicide Suicide % black, % male, median age, Index: Index: 0 Index: 0 unemployment rate, poverty, decrease income, home ownership, college Permit: Permit: 0 enrollment, transience, population decrease Mental: 0 Mental: 0 change, divorce, church Mental: Dealer Dealer membership, etc. decrease decrease decrease Other: 0 Other 0 Gun ownership: various proxies Dealer: decrease Other: 0 Unemployment, divorce Decrease Increase Decrease % male, % 35-64, % black, % n/a n/a Decrease urban, population density; % population change, divorce rate, crime rate, unemployment rate % black, median age, % urban, 0 0 0 divorce rate Gun ownership: Wright survey None Decrease 0 0 None Decrease "Other" Overall: increase decrease male: decrease female: 0 Divorce rate, unemployment rate Wait: n/a n/a decrease Mental: decrease White male suicide rates only: n/a n/a Decrease age, median income, unemployment rate, occupational prestige, % catholic, region % unemployed, % male, % n/a n/a 0 youth, % white collar, % blue collar, % foreign born continued
|
From page 188... ...
TABLE 7-5 Interrupted-Time-Series Studies of Gun Laws and Suicide Time Periods Source Areas Compared Compared Gun Law Lester (2000) Canada 1970-1996 1978 Bill C-51 Carrington Canada 1969-1976; 1978 (1999)
|
From page 189... ...
FIREARMS AND SUICIDE 189 Results Results: Results: Gun Nongun Overall Controls and Strata Suicide Suicide Suicide None Seller: n/a decrease increase Buyer: Buyer: decrease increase Carry: 0 Carry: 0 None n/a n/a Decrease % unemployed, median education, n/a n/a 0 % interstate migrants, % college grads, % white collar, median income, % foreign born, % young adult, log of population Per capita income, median Decrease n/a 0 education, % male, police per capita, % nonwhite, population density, licensed hunters Change in Change in Change in Gun Suicide Nongun Suicide Overall Suicide After Gun Law After Gun Law After Gun Law Decrease Increase Increase Trend No change in Trend flattens for trend for males flattens for males males Trend varies Trend varies by Trend varies by age, sex age, sex by age, sex Trend varies by Trend varies by Trend varies by urban/rural, sex urban/rural, sex urban/rural, sex Not Trend Trend significant downward downward Decrease Not significant Not significant continued
|
From page 190... ...
This decrease, however, was accompanied by an offsetting increase in nongun suicide, so that the net effect on overall suicide rates was not significant (.54 per 100,000; with a 95 percent confidence interval = 1.27 to 0.19)
|
From page 191... ...
They, too, found some reduction in gun suicides among children in states with stricter gun storage laws, but no reduction of overall suicide rates.
|
From page 192... ...
States, regions, and countries with higher rates of household gun ownership have higher rates of gun suicide. There is also cross-sectional, ecological association between gun ownership and overall risk of suicide, but this association is more modest than the association between gun ownership and gun suicide; it is less consistently observed across time, place, and persons; and the causal relation remains unclear.
|
From page 193... ...
First, there is a cross-sectional association between rates of household gun ownership and the number and fraction of suicides committed with a gun that appears to be much more consistent than, for example, the crosssectional association between gun ownership and gun homicide. There also appears to be a cross-sectional association between rates of household gun ownership and overall rates of suicide, reported by investigators on both sides of the gun policy debate.
|
From page 194... ...
Although some knowledge may be gained from further ecological studies, the most important priorities appear, to the committee, to be improved data systems, improved individual-level studies of the association between gun ownership and suicide, and a more systematic analysis of the effect of firearms laws and related interventions on the risk of suicide. Proxy Measures of Gun Ownership The association between gun ownership and gun suicide has led to recommendations for the use of the fraction of suicides committed with a firearm (FS/S)
|
From page 195... ...
It would be useful to have an ongoing, longitudinal study that determines both predictors of gun ownership and other known risk factors for suicidal thoughts, nonlethal suicidal behaviors, and completed suicide. Added detail about method choice and correlates of gun ownership would help to clarify
|
From page 196... ...
Further Policy Studies Suicide prevention has rarely been the basis for public support of the passage of specific gun laws, but effects on suicide rates could be an unintended by-product of such laws, and the effects of different firearms policy interventions on suicide remain poorly understood. Thus, the committee recommends further studies of the link between firearms policy and suicide.
|
From page 197... ...
In our sample population, the odds of suicide among gun owners were 60/ 399,940, and the odds of suicide among nongun owners were 40/599,960. The odds ratio can then be defined as the odds in favor of the outcome in the exposed group, divided by the odds in favor of the outcome in the unexposed group.
|
From page 198... ...
But the symmetry of the odds ratio allows us to estimate the risk of the outcome, given exposure, from information about the odds of exposure, given the outcome. Attributable Risk In fact, by themselves, neither the odds ratio nor the risk ratio can assist policy makers who need to compare the number of occurrences that could be altered through intervention with the costs of the intervention.
|
From page 199... ...
2.25 to 1. The "rare outcome" assumption is satisfied, which simplifies the calculations; we can treat the odds ratio as a risk ratio and calculate incidence rates and attributable risks as follows: The total incidence of suicide in the population is equal to the incidence of suicide among gun owners, times the probability of being a gun owner, plus the incidence of suicide among nongun owners, times the probability of not being a gun owner, i.e.: (5.1)
|
From page 200... ...
The attributable risk is the difference between the probability of suicide among gun owners, and the probability of suicide among nongun owners: 15 6.67 8.33 suicides per 100,000 attributable to gun ownership. The interpretation of this attributable risk depends on the actual causal mechanism linking exposure and outcome.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.