Document Type

Article

Publication Date

2026

DOI

10.1101/2025.08.29.25334693

Publication Title

medRxiv

Pages

44 pp.

Abstract

Suicides cause more than 49,000 deaths per year in the United States, including 55% associated with the use of a firearm. Across states and counties in the US, suicide mortality exhibits substantial geographical and sociodemographic heterogeneity. However, the role of large-scale social networks in shaping this variation remains underexplored. To assess how both the risk of suicide mortality and the effect of firearm restriction policies propagate through inter-county social ties, we integrate data on county-level suicide mortality (2010–2022) and the Facebook Social Connectedness Index (SCI), a continuous measure of the strength of social ties between counties used to derive weighted averages of neighboring counties’ out-comes. First, using two-way fixed effects regression models with sociodemographic, economic, and spatial controls, we find that a one-standard-deviation increase in the SCI-weighted average suicide mortality rate of connected counties is associated with an increase of 2.78 suicide deaths per 100,000 people in the focal county (95% CI: 1.06-4.50). Second, we examine Extreme Risk Protection Orders (ERPOs), state-level policies that allow temporary restriction of firearm access for individuals at risk of self-harm. Using a similar statistical approach, we show that counties with stronger social ties to counties located in ERPO-implementing states experience reductions in suicide mortality, even without local policy enactment. Specifically, we find that a one-standard-deviation increase in ERPO social exposure is associated with a decrease of 0.214 suicide deaths per 100,000 people in the focal county (95% CI: 0.0866-0.342). Such a protective association persists when adjusting for geographical proximity and including state-by-year fixed effects that capture time-varying state-level factors. In sum, our findings suggest that social networks can facilitate the diffusion of both harmful exposures and protective interventions. This socio-spatial structuring of suicide mortality underscores the need for prevention strategies that incorporate social network topology, alongside more traditional approaches based on geographical targeting.

Data Availability

Article states: "Mortality data was obtained from NVSS, managed by the National Center for Health Statistics (NCHS) [49]. Due to confidentiality concerns, this data set is not publicly accessible, but can be requested from NCHS at https://www.cdc.gov/nchs/nvss/ nvss-restricted-data.htm. Social determinants of health (SDOH) covariates for 2010–2020 were obtained from the Agency for Healthcare Research and Quality (AHRQ) SDOH Database (https://www.ahrq.gov/sdoh/data-analytics/sdoh-data.ht ml); for 2020–2022, SDOH covariates were constructed from US Census Bureau products (American Community Survey [ACS] 5-year estimates; see https://www.census.gov/p rograms-surveys/acs/data.html). County-level political affiliation data were obtained from the MIT Election Data and Science Lab, County Presidential Election Returns 2000- 2024, available through Harvard Dataverse at https://doi.org/10.7910/DVN/VOQCHQ [48]. The social connectedness index (SCI) is available through Facebook (Meta) Data for Good at https://dataforgood.facebook.com/dfg/tools/social-connectedne ss-index. For age-adjusted suicide mortality, annual population denominators stratified by 18 five-year age groups were drawn from CDC WONDER Bridged-Race Postcensal Population Estimates (https://wonder.cdc.gov/single-race-population.html)."

Comments

This article is a preprint and has not been peer-reviewed. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

Original Publication Citation

Tiwari, K., Rahimian, M. A., Charpignon, M.-L., Giabbanelli, P. J., & Kumar, P. (2026). Socio-spatial patterns of suicide mortality in the United States. medRxiv. https://doi.org/10.1101/2025.08.29.25334693

ORCID

0000-0001-6816-355X (Giabbanelli)

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