Increases in local homicide rates in U.S. counties are linked to higher suicide rates the following year, particularly when firearms are involved, according to Rutgers researchers.
A new study , published in Social Science & Medicine, examined data spanning more than 50 years to see how these patterns vary by race, firearm involvement and whether communities are urban or rural. The findings highlight how local violence can elevate suicide risk, reinforcing the need for integrated approaches to violence and suicide prevention.
"Local violence doesn't only harm the victims – it destabilizes entire communities in ways that increase the risk of suicide," said Daniel Semenza , director of research at the New Jersey Gun Violence Research Center and lead author of the study. "Violence prevention is suicide prevention."
The analysis draws from 159,601 county-year observations in 48 states, covering annual homicide and suicide data from 1968 to 2019. Researchers used advanced statistical modeling to isolate the impact of homicide on suicide rates, controlling for economic and demographic changes. They also examined variations by firearm involvement, racial composition (Black and white communities) and geographic context (urban versus rural), revealing important differences across populations.
The results show that a one-point increase in a county's homicide rate predicted a 3.6% rise in suicide rates the following year. The connection was even stronger for firearm-related deaths, where increases in firearm homicides were linked to a 5.7% rise in firearm suicides. The effect was most pronounced in rural counties and among white populations, though Black communities also were affected, albeit to a lesser extent.
Researchers said the findings suggest communities experiencing high levels of violence face not only the immediate harms of homicide but increased risk of suicide, especially when guns are involved. The research challenges the assumption that homicide and suicide are separate public health problems, showing they are interconnected and influenced by many of the same social and structural factors, they said. As a result, suicide prevention strategies must include violence prevention efforts, with special attention to firearm access, structural inequality, and rural health disparities.
"Interpersonal and self-directed violence are interconnected and should be treated as such," said Semenza, an associate professor at the Rutgers School of Public Health and Rutgers University-Camden.
