Association between suicide and exposure to homicide in urban neighborhoods: A spatial analysis

Suicide is a leading cause of premature mortality. Understanding how social and environmental exposures in urban communities affect suicidality is crucial for the development of population-based interventions to reduce suicide... [ view full abstract ]

Suicide is a leading cause of premature mortality. Understanding how social and environmental exposures in urban communities affect suicidality is crucial for the development of population-based interventions to reduce suicide rates. Previous research suggests that exposure to community violence and perpetration of violence are associated with higher risk for suicidality. We used vital statistics records from California, geocoded to address of the decedent, to examine whether proximity to homicide was associated with the occurrence of suicide in urban census tracts. For each urban tract (n=7194) and each month in 2012 (the most recent year for which data are available), we computed the number of homicides during the same month, previous month, and 12 months prior within buffer zones of varying distances of the tract. We found that proximity to homicides was negatively associated with the likelihood that a suicide would occur in a given tract-month after controlling for demographic factors, seasonality, other confounders, and spatial and temporal autocorrelation. Estimates suggest that elimination of exposure to homicides would result in a 6.4% increase in the number of tract-months with one or more suicides (95% confidence interval: 3.2 – 9.5%). This relationship was stronger in neighborhoods that were poorer, younger, and less socially cohesive. Results were robust to a wide variety of sensitivity tests. We hypothesize that violence can be directed inward or outward and that our study is capturing the potential substitution of outward- and inward-directed violence. Further investigation is needed to identify the drivers this association.