Effects of Risk-Based Firearm Seizure Laws in Connecticut and Indiana on Suicide Rates, 1981-2015

Objective: This study evaluated whether risk-based firearm seizure laws in Connecticut and Indiana affect suicide rates.

Methods: A quasi-experimental design using annual state-level panel data from the 50 states between 1981 and 2015 was used. When analyses controlled for a range of risk factors for population-level suicide rates, the effects of Connecticut and Indiana's firearm seizure laws on firearm and nonfirearm suicide rates were evaluated by using the synthetic-control methodology and difference-in-place placebo tests. Sensitivity analyses employed regression-based difference-in-differences analyses with randomization inference.

Results: Indiana's firearm seizure law was associated with a 7.5% reduction in firearm suicides in the ten years following its enactment, an effect specific to suicides with firearms and larger than that seen in any comparison state by chance alone. Enactment of Connecticut's law was associated with a 1.6% reduction in firearm suicides immediately after its passage and a 13.7% reduction in firearm suicides in the post-Virginia Tech period, when enforcement of the law substantially increased. Regression-based sensitivity analyses showed that these findings were robust to alternative specifications. Whereas Indiana demonstrated an aggregate decrease in suicides, Connecticut's estimated reduction in firearm suicides was offset by increased nonfirearm suicides.

Conclusions: Risk-based firearm seizure laws were associated with reduced population-level firearm suicide rates, and evidence for a replacement effect was mixed.