Abstract
IMPORTANCE: While numerous states have enacted laws to reduce access to firearms among high-risk individuals, the evidence regarding the associated outcome of reducing firearm suicide has been mixed, in part due to methodological limitations. OBJECTIVE: To examine the association between state firearm laws and firearm-related suicide deaths across all 50 US states during the period from 1976 to 2024. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study, conducted in December 2025, used a difference-in-differences fixed-effects panel regression with Prais-Winsten correction applied to annual state-level data on firearm-related suicides from all 50 US states from January 1976 through December 2024. Sample data were obtained from the Centers for Disease Control and Prevention-maintained Web-based Injury Statistics Query and Reporting System. EXPOSURES: Six firearm laws with prior evidence or theoretical plausibility of affecting risk of suicide: (1) required permits to purchase handguns; (2) waiting periods for firearm purchases; (3) laws requiring permits for concealed carry; (4) minimum age requirements; (5) extreme risk protection order laws; and (6) state permit requirements for gun dealers. Laws were modeled with a 2-year lag. MAIN OUTCOMES AND MEASURES: The primary outcome was annual, age-adjusted, state-specific firearm suicide rate, and the negative control outcome was nonfirearm suicide rate. Models accounted for serial autocorrelation and heteroskedasticity in the data and adjusted for a range of sociodemographic covariates. RESULTS: Across the study period, 2450 observations were collected. The mean overall suicide rate was 13.7 deaths per 100 000 with 7.9 deaths per 100 000 for firearm-related suicide and 5.8 deaths per 100 000 for non-firearm-related suicide. Firearm suicide rates varied 8-fold across states in 2024 (1.8 deaths per 100 000 in New York vs 15.1 deaths per 100 000 in Wyoming). Handgun permit laws (-6.7%; 95% CI, -9.7% to -3.7%), waiting periods (-12.5%; 95% CI, -22.1% to -1.7%), and requirements for a license for concealed carry (-8.9%; 95% CI, -13.1% to -4.8%) were significantly associated with decreases in firearm suicide rates but not with nonfirearm suicide rates. States with 1 (-8.1%; 95% CI, -11.4% to -4.7%), 2 (-12.5%; 95% CI, -16.3% to -8.5%), or all 3 (-25.3%; 95% CI, -34.2% to -15.2%) of these laws (handgun permit requirements, waiting periods, and concealed carry permits) had progressively lower firearm suicide rates. CONCLUSIONS AND RELEVANCE: In this cross-sectional study analyzing data from 49 years and 50 states, permit-to-purchase requirements for handguns, waiting periods, and the requirement for a license for concealed carry were each independently and cumulatively associated with significantly lower firearm suicide rates.