Gun violence and mental health issues, the two are often linked by politicians, in the media and in the minds of the general public. But a new study from the journal Preventive Medicine says that's not the case.

"Contrary to what the public generally thinks — that mental illness causes violence — our study suggests that the mental illness symptoms we examined were not related to gun violence," said lead author Yu Lu, a postdoctoral research fellow at the University of Texas Medical Branch in Galveston.

The study looked at more than 600 adults with an average age of 22 and asked questions about mental health related to anxiety, depression, post-traumatic stress disorder, stress, borderline personality disorders and impulsivity.

The researchers also asked respondents whether they have ever threatened anybody with a gun, and whether they carried a gun outside the home. The study specifically excluded hunting and target practice as reasons for carrying the gun outside the home.

After controlling for gun access and ownership, the authors found that mental health is not "at the root of gun violence." Instead, having access to a gun proved "especially strong in predicting gun carrying and threatening someone with a gun."

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Impulsivity was linked with carrying guns outside the home and hostility was associated with threatening people. The Hostility is by definition "a cognitive trait," the study says. But it's also characteristic of some mental health problems.

The report shows that strategies to reduce anger and hostility might help to lower the risk of gun violence.

One limitation of the study is that it only looked at some mental health factors, but others, such as schizophrenia, were not considered. But the real problem, author Lu said, is that there simply aren't enough gun violence studies overall.

In any case, though, she said, this study concludes that "we should not stigmatize people with mental health problems, we should not assume they are dangerous."

"Mental illness is not associated with gun violence," she said.

Numerous studies have shown that people with mental illness are more likely to be victims of violence — rather than perpetrators.

This reporting is part of Call to Mind, MPR initiative to foster new conversations about mental health.