To investigate the impact of the Australian National Firearms Agreement (NFA) on suicide and assault mortality.
We conducted a retrospective cross-sectional difference-in-difference study of the impact of the NFA on national mortality rates in the Australian population from 1961 to 2015.
The NFA had no additional statistically observable impact on firearm-related suicides in women (P = .09) and was associated with a statistically significant increase in the trend in men (P < .001). Trends in non-firearm-related suicide deaths declined by 4.4% per year (95% confidence interval [CI] = 4.1%, 4.8%) in men after the introduction of the NFA and increased in women by 0.3% (95% CI = 0.1%, 0.7%). Trends in non-firearm-related homicides declined by 2.2% per year (95% CI = 1.5, 3.8%) in women and 2.9% per year (95% CI = 2.0%, 3.7%) in men after the introduction of the NFA, with a statistically significant improvement in trends for women (P = .04) but not for men (P = .80).
The NFA had no statistically observable additional impact on suicide or assault mortality attributable to firearms in Australia.