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A Massive New Study Puts a Pin in One of the Oldest Myths About Mental Illness

Researchers find that those who have a mental illness are more likely to be the victim of a violent crime.

Among the many questions asked after every mass shooting: What, if anything, is the connection between mental illness and violence? It's a link that's reinforced regularly by the national news media: A 2016 John Hopkins University analysis found that more than a third of all news stories about mental-health conditions over the last two decades tied mental illness to violent crime.

new study published in JAMA Psychiatry dispels that relationship. Study authors Jeffrey Swanson and Charles Belden found that, not only is the connection shoddy—the 44-plus million American adults with a mental illness account for between 3 and 5 percent of violent crimes—but in fact those who have a mental illness are more likely to be the victim of a violent crime. Further, one-quarter of all mentally ill Americans are the victim of a violent crime per year, a figure that's well above the existing rates of violent victimization across the United States.

How then to explain the previously reported link between mental illness and violence? Swanson and Belden argue that, in past research, methodology regarding the relationship between mental health and crime were subject to limited sample sizes of a few thousand individuals. Swanson and Belden's study, by contrast, incorporates the largest sample size yet, using data from a cohort of more than two million individuals in Denmark, tracked across several years. Their research found that the presence of mental illness tends to increase a subject's long-term risk of enduring violent crime, a trend that they say "affects people with disorders across the diagnostic spectrum, including those with substance use and personality disorders."

Despite the radically different social and political make-ups of Denmark and the U.S., the presence of a mental illness tends to signal future difficulties for individuals in both nations—the difference is the comparatively larger prevalence of violence overall in the U.S. One study cited by the authors indicated that the average outpatient in Chicago experienced violence at a rate of 234 instances for every 1,000; by contrast, that rate is an average of 11.8 instances for Danish outpatients. This means that, not only are the mentally ill subject to violence at higher rates in both countries—the average national violent crime rates in the U.S. and Denmark, respectively, are 20.1 per 1,000 and 5.4 per 1,000—but that mentally ill Americans are especially prone to violent victimization at a staggering rate.

If the mentally ill are more vulnerable in both countries, why is such vulnerability so much more pronounced in the U.S.? The source of this discrepancy, the authors argue, is an important reminder of an overarching factor that plays a significant role in shaping both criminality and mental illness: relative poverty. The authors argue that Denmark's especially expansive investment in a social safety net—one that's made the country a European model for both sustainable welfare systems and corporate social responsibility (within limits, of course)—is partially responsible for the low rates of violent victimization among the mentally unwell: better access to resources means a better quality of life. While the U.S. spends a comparable amount of its public-health budget on mental-health services as other advanced economies, Americans still suffer from more mental disorders than anyone else on the planet (and most of that mental-health funding goes to prescription medication). As a result, the mentally ill remain stuck in a cycle of poverty that only heightens their exposure to violent crime.

This is the more nuanced reality of crime and mental illness: While a serious, untreated mental-health issue can yield unpredictable results—see Devin Patrick Kelly, the man who killed 26 people in Sutherland Springs, Texas, in 2017—the vast majority of those suffering from a mental-health disorder seek some form of treatment yet somehow. But all the resources in the world can't account for another major barrier to effective treatment: the stigma surrounding mental illness. While mentally ill people are proven in study after study as more likely to end up the victims of violence than they are the perpetrators, the perception of mental-health issues as a path to violence and dangerous behavior can only isolate those who would benefit most—and keep them locked in a spiral of violent victimization.