State laws regulating access to handguns are associated with lower overall suicide rates

by Michael D. Anestis, Ph.D.

A few months ago, I posted here about a study that several students and I had published in the American Journal of Public Health looking at the relationship between a series of state laws regulating handgun ownership and overall suicide rates.  The study demonstrated a robust effect of regulations on suicide rates, further highlighting the importance of managing access to highly lethal means when considering suicide prevention.  In that paper, my colleagues and I selected laws based upon their coverage by the NRA-ILA, with the idea being that we wanted to ensure that nobody could accuse us of cherry picking laws to manipulate the results (after all, the NRA picked the laws).  That being said, I don't think the laws we studied in that paper were the ones likely to exhibit the strongest effect.  Instead - based on David Klonsky and Alexis May's Three-Step Theory of Suicide, which posits that access to and familiarity with lethal means is an important component of the capability for suicide - I thought background checks, waiting periods, gun lock requirements, and restriction of open carry would be better candidates.  These laws, after all, should diminish access and exposure to handguns.

All this being said, with the initial study published, Joye and I decided to examine these other laws and the results were unambiguous in their support of the potential role of legislation of handguns with respect to overall suicide rates.  This paper was also just published in the American Journal of Public Health.  If you want a quick summary of the results, click on the Youtube video below, in which I explain the results in just over a minute.  Below the video, I will explain them in more detail and reflect upon their implications.

For our first set of analyses, we tested each of the four laws (background checks, waiting periods, gun lock requirements, restriction of open carry), examining whether the presence of the law was associated with a lower overall suicide rate, firearm suicide rate, and percentage of suicides resulting from firearms in 2013 (the most recent year with official data available), even after accounting for age, education, poverty, race/ethnicity, and population density.

This table shows you the different rates in states with versus without each of the laws:

Variable	No.	Statewide Suicide Rate for 2013, Mean (SD)	Statewide Suicide by Firearm Rate for 2013, Mean (SD)	Statewide Deaths by Firearms for 2010, %, Mean (SD)
Waiting period
Yes	11	11.45 (2.82)	4.43 (2.57)	35.8 (17.1)
No	40	15.72 (3.72)	8.98 (3.07)	55.8 (11.6)
Background check
Yes	17	11.42 (3.06)	4.53 (2.62)	36.8 (16.2)
No	34	16.49 (3.18)	9.74 (2.43)	58.8 (7.6)
Open carry restricted
Yes	20	12.16 (3.44)	5.58 (3.38)	42.1 (18.9)
No	31	16.50 (3.27)	9.56 (2.60)	57.5 (8.0)
Gun lock required
Yes	4	9.20 (0.91)	2.68 (1.02)	28.5 (8.0)
No	47	15.28 (3.72)	8.45(3.25)	53.4 (14.1)

A quick look makes it clear that the rates were quite different in those with versus without various forms of legislation.

We next looked at whether these laws had a significant effect on each of those outcomes even after controlling for the list of demographic variables I listed earlier.

Variable	Statewide Suicide Rate for 2013			Statewide Suicide by Firearm Rate for 2013			Statewide Proportion of Suicide Deaths by Firearms for 2013
	R2	b(95% CI)	ph2	R2	b (95% CI)	ph2	R2	b (95% CI)	ph2
Set - Waiting Period	0.43			0.60			0.74
Population density		0.000 (–0.001, 0.001)	0.00		0.000 (0.000, 0.001)	0.01		0.000 (0.000, 0.000)	0.02
% of state below poverty     line		–0.211 (–0.633, 0.211)	0.02		–0.112 (–0.425, 0.201)	0.01		0.005 (–0.006, 0.016)	0.02
% aged|>|25 y with     college degree		–0.293* (–0.582, 0.003)	0.09		–0.360** (–0.574, 0.145)	0.21		–0.014** (–0.021, 0.006)	0.23
% White		0.057 (–0.012, 0.126)	0.06		0.054* (0.003, 0.105)	0.09		0.002* (0.000, 0.004)	0.11
Median age		–0.318 (–0.727, 0.091)	0.05		–0.298 (–0.602, 0.005)	0.08		–0.011* (–0.022, 0.000)	0.09
Waiting period		2.271 (–0.339, 4.881)	0.07		2.366* (0.430, 4.303)	0.12		0.072* (0.003, 0.140)	0.09
Set - Background Check	0.51			0.67			0.77
Population density		0.000 (–0.001, 0.001)	0.00		0.000 (–0.001, 0.001)	0.00		0.000 (0.000, 0.000)	0.06
% of state below poverty     line		–0.187 (–0.565, 0.191)	0.02		–0.074 (–0.351, 0.203)	0.01		0.006 (–0.004, 0.016)	0.03
% aged|>|25 y with     college degree		–0.169 (–0.445, 0.108)	0.03		–0.245* (–0.448, 0.043)	0.12		–0.010** (–0.017, 0.003)	0.15
% White		0.046 (–0.018, 0.109)	0.05		0.047* (0.001, 0.094)	0.09		0.002* (0.000, 0.003)	0.10
Median age		–0.254 (–0.637, 0.129)	0.04		–0.253 (–0.533, 0.028)	0.07		–0.009 (–0.019, 0.001)	0.07
Background check		3.519** (1.294, 5.744)	0.19		3.146***(1.517, 4.775)	0.26		0.099** (0.040, 0.157)	0.21
Set - Open Carry	0.50			0.64			0.75
Population density		0.000 (–0.001, 0.001)	0.00		0.000 (–0.001, 0.001)	0.00		0.000 (0.000, 0.000)	0.05
% of state below poverty     line		–0.136 (–0.511, 0.239)	0.01		–0.024 (–0.309, 0.261)	0.00		0.008 (–0.003, 0.018)	0.05
% aged|>|25 y with     college degree		–0.215 (–0.486, 0.057)	0.05		–0.292** (–0.499, 0.086)	0.16		–0.012** (–0.019, 0.004)	0.18
% White		0.051 (–0.011, 0.114)	0.06		0.055* (0.008, 0.103)	0.11		0.002* (0.000, 0.004)	0.12
Median age		–0.414* (–0.787, 0.040)	0.10		–0.394** (–0.677, 0.110)	0.15		–0.014* (–0.024, 0.003)	0.14
Open carry restricted		3.025** (1.092, 4.957)	0.18		2.381** (0.912, 3.850)	0.20		0.066 * (0.013, 0.120)	0.13
Set - Gun Locks	0.46			0.60			0.76
Population density		–0.001 (–0.002, 0.001)	0.03		0.000 (–0.001, 0.001)	0.01		0.000 (0.000, 0.000)	0.12
% of state below poverty     line		–0.024 (–0.421, 0.374)	0.00		0.062 (–0.243, 0.367)	0.00		0.011* (0.001, 0.021)	0.10
% aged|>|25 y with     college degree		–0.144 (–0.448, 0.160)	0.02		–0.241* (–0.474, 0.008)	0.09		–0.009* (–0.016, 0.001)	0.10
% White		0.072* (0.009, 0.135)	0.11		0.072** (0.024, 0.120)	0.17		0.002** (0.001, 0.004)	0.18
Median age		–0.356 (–0.748, 0.037)	0.07		–0.349* (–0.650, 0.048)	0.11		–0.012* (–0.022, 0.002)	0.12
Gun lock required		4.085* (0.456, 7.713)	0.11		3.073* (0.291, 5.855)	0.10		0.137** (0.043, 0.230)	0.17

There are several important things to note in this table.  First of all, almost every single effect was statistically significant (which is remarkable on its own, given that there was a sample size of only 50 states and DC) and the one non-significant one had a medium effect size.  Second, many of the effect sizes were enormous and each analysis accounted for a remarkably high percentage of the variability in our outcomes.  Put another way, the relationship between law and suicide rates was huge and this isn't a situation where we talk about statistical significance with little real world value.  Instead, we accounted for the majority of the variability in most of our outcomes.  That's simply not something you find often in social sciences, particularly when you talk about low base rate events like suicide.

For our next set of analyses, we wanted to test whether each law had an indirect effect on overall suicide rates through the percentage of suicides resulting from firearms.  What this means is that we wanted to see if the way these laws impact overall suicide rates (not just firearm suicide rates) is through their impact on the percentage of suicide deaths resulting from firearms.  Results consistent with that idea would indicate that the laws work through one or more of the following ways: reducing the overall number of attempts, leading people to attempt with less lethal means, or reducing the number of handguns owned within the state.  The table below shows you the results.

Independent Variable	R2	Coefficient (SE; P) or Bootstrap Coefficient (SE; 95% CI)	Ratio Indirect:Total	k2
Waiting period	0.42		0.67	0.29
Total		-4.28 (1.21; .001)
Direct path		-1.42 (1.25; .261)
Indirect path		-2.86 (0.93; -5.30, -1.42)
Background check	0.46		0.45	0.26
Total		-5.07 (0.93; <.001)
Direct path		-2.77 (1.21; .026)
Indirect path		-2.30 (0.89; -4.28, –0.73)
Open carry	0.29		0.44	0.25
Total		-4.35 (0.96; <.001)
Direct path		-2.42 (0.97; .016)
Indirect path		-1.93 (0.69; -4.36, –0.47)
Gun lock	0.18		0.59	0.25
Total		-6.07 (1.88; .002)
Direct path		-2.47 (1.77; .169)
Indirect path		–0.3.60 (1.01; -6.06, -1.93)

As you can see, in each case, the laws had a significant indirect effect through the percentage of suicides resulting from firearms and, here again, the effect sizes were impressively large.

So before moving on, let's recap what we've learned so far. 

(1) States with one of these laws in place  had lower overall suicide rates, firearm suicide rates, and percentage of suicides resulting from firearms. 

(2) The laws appear to impact overall rates largely through their ability to reduce the percentage of suicides resulting in firearms.

A reasonable critique of those findings would be that we looked only at a single year.  Given that, it could be that the states that had these laws in place would have had lower suicide rates anyway and that the laws themselves aren't the causal force.  To address this, we acquired a list of states that changed any of these laws from 2009-2013 from the Law Center to Prevent Gun Violence.  We found four such changes.  During this period, California restricted open carry, DC extended their waiting period, Oklahoma restricted open carry, and South Dakota repealed their waiting period.  So what happened with these changes?

• In the year after restricting open carry, California saw a 3.5% decrease in its suicide rate whereas the nation as a whole (excluding California) saw a 2.1% increase.  From the year of enactment through 2013, California saw a 1.0% decrease in their suicide rate whereas the nation as a whole saw a 2.7% increase.

• In the year after extending their waiting period, DC saw a 2.2% decrease in its suicide rate whereas the nation saw a 2.1% increase.  From the year of enactment through 2013, DC saw a 1.5% decrease whereas the nation saw a 2.7% increase.

• In the year after restricting open carry, Oklahoma saw a 1.7% decrease in its suicide rate whereas the nation saw a 0.6% increase.  This law was changed in 2012, so the data are the same for the year of enactment through 2013.

• In the year after repealing their waiting list, South Dakota saw a 7.6% increase in its suicide rate whereas the nation saw a 3.3% increase.  From the year of enactment through 2013, South Dakota saw an 8.9% increase whereas the nation saw an 8.2% increase.

So...enact a law and your rate goes down in subsequent years even as the national rate goes up.  Repeal a law and your rate increases more steeply than that of the nation as a whole.

Before wrapping up, we ran one last series of analyses.  To provide some context, we examined the relationship between three non-controversial traffic laws (no texting while driving, hands free cell phone use, and primary enforcement of seatbelt use) on traffic deaths, controlling for the same demographic factors.  In each case, the traffic law was not significantly related to traffic deaths.  Does this mean texting while driving, using a hand held cell, or not using your seatbelt aren't dangerous?  Of course not.  What it means is that legislating those behaviors doesn't seem to impact death.  Indeed, it is a cultural norm to be safe when it comes to such behaviors, so individuals do this on their own and the legislation might not be necessary for the behaviors to take root and have their impact on traffic injuries and deaths.  That same cultural norm is not present for gun safety and, as such, the laws have a strong effect, as they increase the odds of gun safety.  Nobody is proposing the legislation solves everything or is equally effective for all behaviors.  Rather, it seems like legislation might prove useful when cultural norms value unsafe behavior over safe behavior and individuals are not intrinsically motivated to act safely.

So what does this all mean?  Our results point towards legislation as one potentially powerful tool in substantially reducing the suicide rate.  That effect is likely explained largely through a decrease in gun ownership and is consistent with the mountains of evidence showing that when you restrict access to lethal means, the suicide rate goes down and those reductions are sustained.  Given evidence contradicting the common belief that "those who really want to die will simply find another way if you take the gun away," this represents a potential solution to a serious public health concern.

That being said, large portions of this country strongly oppose gun regulation and, in some parts of the country, that outcome simply isn't realistic.  Because of this, as a resident of Mississippi I propose the following:

The quickest and most powerful way for us to reduce the suicide rate in the US might be for suicide prevention experts to partner with state governments and gun safety educators to develop publicity and education campaigns emphasizing gun safety among gun owners.  When we talk about guns, we have to start talking about suicide (which accounts for well over half of all gun deaths in the US) and when we talk about guns and suicide, we might need to think less about regulation and more about the common ground we can find through education.  I don't like guns, but that's irrelevant here.  What matters is that we all dislike suicide and want to prevent it.  Here's our common path.  Don't single out the mentally ill - folks showing up in emergency rooms and psychology clinics are not representative of most the individuals who die by suicide using a gun - but instead focus at the population level and provide legitimate education on suicide risk factors and means safety options for all gun owners when they acquire a gun.  Promote statewide conversations about suicide.  Shift the cultural norm such that people see having somebody keep their gun for them when they're upset as akin to having somebody keep their keys when they've consumed alcohol.  Means safety will not eliminate suicide, but it will reduce the overall capacity for suicide in our nation, thereby increasing the strength of our various effective therapies that aim to address suicidal thinking.  There aren't often clear paths to robust impacts on severe public health concerns, but this seems to be one.  The question is whether we use this information to inspire productive action or if we waver, pause, and revisit this years later, having failed to save the thousands of lives that might otherwise have been saved.

**********

If you'd like to see some media coverage of this study, you can see some in the New York Times and Mississippi Public Broadcasting.  You can also read an editorial I recently published on this topic in the Hattiesburg American.

Mike Anestis, Ph.D. is the Nina Bell Suggs Professor of Psychology and the director of the Suicide and Emotion Dysregulation lab at the University of Southern Mississippi.