Is There a Link Between Mental Health and Gun Violence?
When Swanson first analyzed the ostensible connection between violence and mental illness, looking at more than ten thousand individuals (both mentally ill and healthy) during the course of one year, he found that serious mental illness alone was a risk factor for violence—from minor incidents, like shoving, to armed assault—in only four per cent of cases. That is, if you took all of the incidents of violence reported among the people in the survey, mental illness alone could explain only four per cent of the incidents.
.. When Swanson broke the samples down by demographics, he found that the occurrence of violence was more closely associated with whether someone was male, poor, and abusing either alcohol or drugs—and that those three factors alone could predict violent behavior with or without any sign of mental illness. If someone fit all three of those categories, the likelihood of them committing a violent act was high, even if they weren’t also mentally ill. If someone fit none, then mental illness was highly unlikely to be predictive of violence.
.. In all of his work, Swanson has found one recurring factor: past violence remains the single biggest predictor of future violence. “Any history of violent behavior is a much stronger predictor of future violence than mental-health diagnosis,” he told me. If Swanson had his way, gun prohibitions wouldn’t be based on mental health, but on records of violent behavior—not just felonies, but also including minor disputes. “There are lots of people out there carrying guns around who have high levels of trait anger—the type who smash and break things,” he said. “I believe they shouldn’t have guns.