Objective:

To analyze the association between state firearm laws and county-level firearm-related suicide rates.

Approach:

• Data Analysis: Investigators analyzed annual data from 637 US counties from 2000 to 2023, using a difference-in-differences panel model.

Key Findings:

• Five out of eight examined state firearm laws were statistically significant in reducing firearm-related suicide rates.
• Firearm-related suicide rates were 14% lower with violent misdemeanor prohibitions.
• Rates were 9% lower with a minimum age of 21 for handgun purchases and laws for extreme risk protection orders.
• Child access protection laws were associated with an 8% lower rate, and handgun purchase permit requirements with a 7% lower rate.
• A monotonic pattern of increasing reductions in suicide rates was observed as the number of laws increased.
• In a negative-control analysis, the five laws were not significantly associated with nonfirearm-related suicide rates.

Interpretation:

The study found a progressive reduction in firearm-related suicide rates with an increasing number of specific firearm laws.

Limitations:

• Observational design limits the ability to establish causality.
• Difficulty isolating the impact of individual laws due to simultaneous enactment.
• Exclusion of smaller rural counties may limit generalizability.
• Gaps in data hindered formal assessment of the parallel-trends assumption.
• Not all firearm laws showed consistent associations.

Conclusion:

Future research should employ multilevel modeling to confirm these findings.

Sources:

• JAMA Network Open