This is a very interesting article:
In 2010, the last year for which complete numbers are available, the number of gun deaths by suicide in the United States outnumbered homicides 19,392 to 11,078. If you add up all American gun deaths that year, including accidents, 3 out of 5 people who died from gunshot wounds took their own lives. Those figures are not an anomaly: With just a few exceptions, the majority of gun deaths in the United States have been self-inflicted every year since at least 1920. This is a startling fact, and one that forces us to realize that, no matter what we may believe about the Second Amendment, the debate over how to reduce the death toll from guns is, to a great extent, a debate about suicide prevention.
“To some people, it’s just totally counterintuitive, because it’s so obvious that if you want to kill yourself, you can always find something else to kill yourself with,” said Barber. “What they assume is that once you’re suicidal, you remain suicidal.” But a preponderance of evidence, including interviews with suicide survivors, indicates that most suicidal acts come during a surprisingly short period during which the person is suffering an acute crisis.
“When you ask people who’ve made attempts and survived,” Miller said, “even attempts that are life threatening and would have proved lethal [without emergency medical care], what they say is, ‘It was an impulsive act, and I’m glad that I’m alive.’”
The central insight for public health researchers is that a lot of lives could be saved simply by making sure that people don’t have access to an extremely lethal weapon during that high-risk period. One striking illustration of this principle can be seen in the experience of the Israeli Defense Forces, which saw a 40 percent drop in suicides after a new rule was introduced forbidding soldiers from taking their guns home with them over the weekend. Though some soldiers may have tried to kill themselves using some less lethal method instead, it appears that scores of lives were saved.
I then went searching for more information. I found that Harvard has compiled a list of studies on gun research and specifically its connection to suicide. I then found a couple places that had compiled some gun numbers (the first link also looks at the correlation with a bunch of other variables) and that led me to the CDC and its data compiler Wonder.
Once there I played around with the numbers and got a bunch of graphs (All courtesy of: Centers for Disease Control and Prevention, National Center for Health Statistics).
First I looked at the relation between the level of gun rights in a state (as compiled by the Brady Campaign) and the total number of deaths in 2010 caused by guns (assaults, suicide, and accidental):
The correlation is -.66, which is pretty strong (the rates of death are age adjusted, but otherwise I did not try to adjust for possible confounders). It looks like more regulation reduces the number of gun deaths, but because of the article, I also looked at gun rights and suicides by gun:
Here the correlation is -.75, even stronger, so I wondered about the relation between gun regulations and murders (officially this is the number of assault deaths):
which has a correlation of only -.05. That’s pretty stunning to me. The Globe article noted that the probability of a suicide depends on the availability of a gun, so I went to look for the percent of residents who are gun owners. Using the data from here, I looked at its correlation with gun deaths and found:
a correlation of -.77 with gun regulations, a correlation of .83 with suicides by gun, a correlation of .72 with all gun deaths, and a correlation of -.03 with gun assault deaths.
Obviously this is very rough data (using grouped data like this will usually inflate the correlation, I made no attempt to control for other variables, I made no attempt to check the data (I assume the CDC data is ok), didn’t try to look at the type of gun used and made no attempt to see if the same pattern holds for counties or other region types), but I still think this can tell us that guns and suicide might be what we should look at.
Aside: here are some other correlations I found:
all deaths by gun from 1999-2004 and 2005-2010: .97 (and .9 between 1999-2004 and 2010)
assault deaths by gun and by other means: .78
suicides by gun and other: .13 (!)
total number of assault and suicide deaths: -.3 (!)