Although gun ownership rates in the United States are much higher than in most other developed countries, the rates of suicide in the United States rank in the middle. Killias (1993), Killias (2001), and Johnson et al. (2000) found that reported rates of household gun ownership were strongly correlated with the fraction of suicides committed with a gun in each country (Spearman’s rho = .79 to .92, p < .001). But the cross-country correlations between household gun ownership and overall rates of suicide have proven to be smaller and statistically imprecise (Spearman’s rho .25, p = .27) (Killias, 2001). Likewise, in an often-cited study, Sloan et al. (1990) compared the rates of gun and nongun suicides in Seattle, Washington, with suicide rates in Vancouver, British Columbia, between 1985 and 1987; they found higher rates of gun ownership are associated with higher rates of gun suicide, lower rates of nongun suicide, and no significant difference in the overall suicide rate between the two cities (relative risk .97, 95% CI .87 to 1.09).
The fraction of suicides in the United States that are committed with a firearm has increased from just over 35 percent in the 1920s to about 60 percent in the 1990s. 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. Clarke and Jones (1989), examined the national prevalence of household gun ownership reported in polls by Gallup and the National Opinion Research Center between 1959 and 1984, comparing these reports with aggregate U.S. suicide rates over the same period. This study found a positive association between the fraction of households owning a handgun and the fraction of suicides committed with a gun (b = .68, p = .001), but no association between household gun ownership and overall risk of suicide (b = .04, p = .85). Azrael et al. (2004) also report a strong linear association between individual and household rates of gun ownership within regions and the fraction of suicides committed with a gun between 1980 and 1998, with cross-sectional beta coefficients ranging from .55 (for individual handgun ownership) to 1.02 (for household gun ownership of any kind), and an inter-temporal coefficient between FS/S and household gun ownership of .905 (s.e. = .355). They did not report the association between gun ownership and overall risk of suicide. Mathur and Freeman (2002) used state-level per capita gun dealership rates to predict adolescent suicide rates from 1970 to 1997. After controlling for state and year fixed effects and number of other observed