The deadly relationship between guns and suicide

James Doti, Tribune News Service

The fascinating thing about economic research is that it moves in ways that often can’t be anticipated. Sometimes, your assumptions are upended.

I was recently part of a research team that showed that people living in states with relatively high taxes tended over time to move to states with lower taxes. Case in point: The states with the highest rates of taxation — New Jersey, California and New York — also had the highest levels and rates of net outward migration.

In the course of that research, I came across statistics that showed New Jersey, California and New York as having the three lowest rates of suicide. How could it be that the three states with the highest tax rates also had the lowest suicide rates?

Perhaps higher taxes allowed for greater funding levels for suicide prevention or mental health programs. Or more likely, I thought, this was simply a spurious relationship and there was something else going on that explained suicide rates. But what was that “something else”?

My eureka moment came when further research revealed that high-tax states like New Jersey, California and New York were among the lowest in rates of gun ownership. At the same time, states like Montana, South Dakota and Wyoming had something else in common besides low tax rates. They also had high rates of gun ownership.

Half of all suicide deaths are caused by firearms. Over the last decade, the number of US suicides by firearm has increased almost 20%, claiming the lives of nearly 22,000 Americans every year. Suicide is now the 10th leading cause of death in the US.

So maybe the “something else” that explains the number of suicides is not the rate of taxation but the more intuitively plausible connection with gun ownership.

To test that, I measured the correlation between the percentage of American adults over 18 who owned guns and the number of suicides per 100,000 individuals over 18 for all 50 states. That correlation was not only statistically significant but higher than the correlation between taxes and suicides.

For example, 20% of adults in California own a gun versus Arizona’s 32%. Given the close relationship I measured for the correlation between gun ownership and suicide for all 50 states, it shouldn’t be surprising that California’s suicide rate of 10.5 per 100,000 individuals was lower than Arizona’s 18.2 per 100,000.

I also found that the 12 states with the highest rates of gun ownership had an average suicide rate of 20 per 100,000 individuals. By contrast, the 12 states with the lowest rates of gun ownership had a significantly lower suicide rate of 12.3 per 100,000. Even more alarming was that the 12 states with the highest rates of gun ownership also had the highest teen suicide rate of 16.6 per 100,000 adolescents ages 15 to 19. That teen suicide rate is roughly double the 8.0 rate for the 12 states with the lowest rates of gun ownership.

I also ran regression tests that suggested if tougher gun regulations were to push gun ownership from its current average of 33% of all adults over 18 to, say, a rate of 29%, the projected number of suicides would decline from the current average of 16.7 suicides per 100,000 individuals to 15.7 suicides per 100,000. Such a decrease would lead to about 3,000 fewer suicides nationwide a year.

It might be argued, though, that if guns weren’t around, suicidal people would find other ways to commit their act. But if this were the case, one would expect states with low rates of gun ownership to have higher rates of non-firearm suicide and vice versa. Such an inverse relationship, however, was not supported in the correlation and regression tests I conducted.

When a gun is more readily available, there is a greater likelihood that it will be used to commit suicide. Other studies have shown that many suicide attempts are impulsive acts. That, in turn, suggests that if a gun is more accessible, it will be easier to act on impulse.

What started out for me as a question about a seemingly inexplicable relationship between taxes and suicides eventually led to compelling findings about the relationship between guns and suicides.