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A Call for Complex Systems and Syndemic Theory in Firearm Violence Research

Published:December 05, 2021DOI:https://doi.org/10.1016/j.amepre.2021.08.026

      INTRODUCTION

      Firearm violence remains an inequitable and significant social burden in the U.S. Annually, firearm violence costs approximately 30,000 lives each year and nearly $165 billion.
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      Despite an ongoing emphasis on curbing the gun violence epidemic,
      • Sanchez C
      • Jaguan D
      • Shaikh S
      • McKenney M
      • Elkbuli A.
      A systematic review of the causes and prevention strategies in reducing gun violence in the United States.
      firearm violence mortality rates have remained relatively stable throughout the 21st century.
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      Further, discrete geographic areas and demographic segments endure a disproportionate burden from firearm violence.
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      ,
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      Firearm homicides in particular have risen in recent years, and these trends have been exacerbated during the coronavirus disease 2019 (COVID-19) pandemic.
      • Donnelly MR
      • Grigorian A
      • Inaba K
      • et al.
      A dual pandemic: the influence of coronavirus disease 2019 on trends and types of firearm violence in California, Ohio and the United States.
      Driven by an array of macrostructural forces and policies that are particularly salient in both the current zeitgeist and empirical literature, including structural racism,
      • Wilson WJ.
      The Truly Disadvantaged: The Inner City, the Underclass, and Public Policy.
      ,
      • Wong B
      • Bernstein S
      • Jay J
      • Siegel M.
      Differences in racial disparities in firearm homicide across cities: the role of racial residential segregation and gaps in structural disadvantage.
      health/healthcare disparities,
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,
      • Formica MK
      • Rajan S
      • Simons N.
      Healthcare indicators and firearm homicide: an ecologic study.
      and liberal firearm access/ownership policies,
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      the longstanding and disproportionate impacts of firearm violence suggest that novel approaches may be needed to understand the underlying causal mechanisms that shape these outcomes and represent potential targets of corresponding preventive efforts. As evidence of the underlying dynamic complexity that characterizes many of these mechanisms continues to emerge, research and prevention based on complex systems–grounded approaches appear especially promising. In particular, syndemic theory may represent a powerful theoretical framework for complex systems–grounded research and prevention that can holistically embody the endemic and novel forces that shape firearm violence and guide high-leverage preventive solutions. Here, the potential of complex systems and syndemic perspectives is demonstrated, with a focus on firearm homicides; however, the potential of these ideas is more broadly applicable.

      RETHINKING CAUSALITY IN FIREARM VIOLENCE: COMPLEX SYSTEMS AND SYNDEMIC PERSPECTIVES

      Endeavors to understand causality in firearm violence research has almost universally fallen within the same paradigm that continues to dominate the social sciences. In the pursuit of discrete risk factors, this paradigm is grounded in 2 key assumptions. First, complex phenomena are best understood by deconstructing them into their component parts to be investigated in isolation. Aggregating these component-based insights can then lead to an understanding of the whole (reductionism). Second, cause–effect relationships are characterized by proportionality and superpositionality (linearity). Therefore, firearm violence research is characterized by methodologies that emphasize variable isolation and analytical techniques that rely on quantitative statistical methods that explain aggregate indicators via probability theory and macroscopic laws of averages.
      • Lemke MK
      • Drake SA
      • Wolf DA
      • Levine N
      • Yang Y.
      Rethinking the nexus of firearm homicides, COVID-19, and social unrest: how syndemic theory and complex systems approaches can innovate understanding and prevention.
      Undoubtedly, the current paradigm in firearm violence research has been critical in explicating numerous causal mechanisms across levels of influence, including distal forces. For example, key ecologic forces that shape gun violence—such as neighborhood characteristics (e.g., socioeconomic disadvantage, residential instability),
      • Lauritsen JL.
      The social ecology of violent victimization: individual and contextual effects in the NCVS.
      social network connectiveness,
      • Sampson RJ.
      Social ecology and collective efficacy theory.
      and social trust
      • Rosenfeld R
      • Baumer E
      • Messner SF.
      Social trust, firearm prevalence, and homicide.
      —have been connected to a diverse array of downstream consequences that reinforce geographic and demographic inequities (e.g., through their detrimental impacts on children).
      • Sharkey P
      • Schwartz AE
      • Ellen IG
      • Lacoe J.
      High stakes in the classroom, high stakes on the street: the effects of community violence on student's standardized test performance.
      However, as this body of literature on firearm violence continues to expand, researchers have started bringing to light a growing list of shortcomings in understanding the causal nature of these events and deficiencies in actions to prevent them.
      • Sharkey P
      • Schwartz AE
      • Ellen IG
      • Lacoe J.
      High stakes in the classroom, high stakes on the street: the effects of community violence on student's standardized test performance.
      For example, although the current paradigm is grounded in linearity, research has revealed the tendency of firearm violence to shape, and be shaped by, inequities in a reciprocal manner, thereby forming feedback loops.
      • Sharkey P
      • Sampson RJ.
      Violence, cognition, and neighborhood inequality in America.
      Additionally, existing studies that investigate the causality of firearm homicides have shown unclear and often contradictory findings when examining risk factors for firearm violence across multiple levels of analysis, such as the influence of specific individual- or community/neighborhood-level risks on gun violence.
      • Lauritsen JL.
      The social ecology of violent victimization: individual and contextual effects in the NCVS.
      ,
      • Sharkey P
      • Sampson RJ.
      Violence, cognition, and neighborhood inequality in America.
      Such findings have been found when investigating domains spanning across individual-level antecedents and racial/ethnic factors to firearm ownership rates and healthcare access.
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      Similar shortcomings have been observed regarding emerging risks associated with firearm violence during the COVID-19 pandemic.
      • Abdallah HO
      • Zhao C
      • Kaufman E
      • et al.
      Increased firearm injury during the COVID-19 pandemic: a hidden urban burden.
      Therefore, the key underlying mechanisms that shape firearm violence have been described as undertheorized.

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      Furthermore, instances of success in prevention initiatives are overshadowed by the aforementioned population-level persistence of, and recent trends in, firearm violence rates.
      Together, these shortcomings may be interpreted as an opportunity to fill an epistemologic and paradigmatic niche in gun violence research and prevention by integrating a new theoretical lens. This lens would no longer be oriented on risk factors but rather would focus on holistically capturing the multifactorial and interactive causal nature of firearm violence over time.
      • Lemke MK
      • Drake SA
      • Wolf DA
      • Levine N
      • Yang Y.
      Rethinking the nexus of firearm homicides, COVID-19, and social unrest: how syndemic theory and complex systems approaches can innovate understanding and prevention.
      Furthermore, this novel perspective should be able to conceptualize how macro-level forces interact with downstream forces to shape firearm violence.
      • Lemke MK
      • Drake SA
      • Wolf DA
      • Levine N
      • Yang Y.
      Rethinking the nexus of firearm homicides, COVID-19, and social unrest: how syndemic theory and complex systems approaches can innovate understanding and prevention.
      In other words, understanding should be focused on those dynamically complex causal mechanisms that generate and perpetuate the disproportionate distribution of these outcomes over time. However, because this perspective directly contrasts with the assumptions that underpin the dominant paradigm, adopting this dynamic complexity lens will necessitate the adoption of alternate theoretical and methodologic approaches. Thus, complex systems approaches constitute a novel paradigm in firearm violence research and prevention that is oriented toward phenomena that are best explained through a dynamic complexity lens. This paradigm aligns with a growing list of researchers who have characterized the causal nature of firearm violence as complex.

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      However, integrating complex systems approaches takes these calls several steps further by emphasizing a paradigmatic shift that holistically embodies those properties of dynamic complexity that have been observed in studies on firearm violence. These properties include, but are not limited to, nonlinearities
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      ,
      • Saadi-Sedik T
      • Xu R.
      A Vicious Cycle: How Pandemics Lead to Economic Despair and Social Unrest.
      and interactions
      • Sanchez C
      • Jaguan D
      • Shaikh S
      • McKenney M
      • Elkbuli A.
      A systematic review of the causes and prevention strategies in reducing gun violence in the United States.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      among dynamic,
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      ,
      • Abdallah HO
      • Zhao C
      • Kaufman E
      • et al.
      Increased firearm injury during the COVID-19 pandemic: a hidden urban burden.
      spatiotemporally distal,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      ,
      • Vella MA
      • Warshauer A
      • Tortorello G
      • et al.
      Long-term functional, psychological, emotional, and social outcomes in survivors of firearm injuries.
      and heterogeneous
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      ,
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      ,
      • Saadi-Sedik T
      • Xu R.
      A Vicious Cycle: How Pandemics Lead to Economic Despair and Social Unrest.
      ,
      • Hohl BC
      • Wiley S
      • Wiebe DJ
      • Culyba AJ
      • Drake R
      • Branas CC.
      Association of drug and alcohol use with adolescent firearm homicide at individual, family, and neighborhood levels.
      causal factors that exhibit adaptation and self-organization
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      and generate the emergence
      • Hohl BC
      • Wiley S
      • Wiebe DJ
      • Culyba AJ
      • Drake R
      • Branas CC.
      Association of drug and alcohol use with adolescent firearm homicide at individual, family, and neighborhood levels.
      of population-level patterns of firearm violence.

      PUTTING THE PIECES TOGETHER: RECONCEPTUALIZING FIREARM VIOLENCE THROUGH THE SYNDEMIC LENS

      Complex systems approaches—and their corresponding theoretical assumptions in particular—may provide newfound insights into the nexus of dynamically complex longstanding (i.e., endemic) and emerging (i.e., novel) forces, or vulnerabilities, that shape the disproportionate burden of firearm violence within geographies and demographies.
      • Lemke MK
      • Drake SA
      • Wolf DA
      • Levine N
      • Yang Y.
      Rethinking the nexus of firearm homicides, COVID-19, and social unrest: how syndemic theory and complex systems approaches can innovate understanding and prevention.
      However, this paradigmatic shift may be daunting for many, especially given the infrequent exposure to these approaches in most academic programs and the limited number of professional training opportunities to acquire proficiency in theory and methodology. Further, the assumptions that define complex systems approaches are innately more difficult than those within the dominant paradigm that more easily coalesce with mental models. Together, these (and other) barriers may hinder the integration of complex systems approaches into firearm violence research and prevention.
      Fortunately, syndemic theory represents an accessible—yet powerful—way of engaging in complex systems–grounded firearm violence research and prevention. Syndemics are defined as the clustering, owing to contextual and social factors, of multiple and adversely interacting disease states (i.e., afflictions) within populations. The co-occurrence of these interacting afflictions leads to increased burden and vulnerability in these populations that then reinforces those macro-level factors, thus creating a reinforcing loop that perpetuates disparities.
      • Singer M
      • Bulled N
      • Ostrach B
      • Mendenhall E.
      Syndemics and the biosocial conception of health.
      Altogether, viewing firearm violence through this lens may provide the theoretical foundation for complex systems-oriented research and prevention that can:
      • 1.
        conceptualize the emergence of interacting firearm violence and associated afflictions as the product of macrostructural and historical policies and forces that have unfolded and continue to unfold over time.
      • 2.
        anticipate how these afflictions may influence endemic and novel vulnerabilities and shape disparities in firearm violence in a nonlinear manner.
      • 3.
        identify innovative and holistic multilevel prevention efforts.
        • Singer M
        • Bulled N
        • Ostrach B
        • Mendenhall E.
        Syndemics and the biosocial conception of health.

      Firearm Violence as an Endemic Syndemic: Macrostructural Drivers and Downstream Impacts

      Longstanding vulnerabilities that are maintained through enduring dynamically complex causal mechanisms and shape the persistent clustering of firearm violence within specific geographies and demographies may constitute an endemic firearm violence syndemic. A conceptual, feedback loop–focused framework of this syndemic is presented in Figure 1, where the following 3 dynamically complex causal mechanisms shape endemic vulnerabilities across multiple levels of influence are explored: (1) structural racism/discrimination, (2) health/health care, and (3) firearm access/ownership. This characterization is intended as an evidence-grounded primer in conceptualizing firearm violence as syndemic, rather than as an inclusive framework that embodies the full array of plausible causal mechanisms. The nested layers in the hierarchy are labeled on the left side of the figure, and the spatiotemporal scale of the dynamic processes that unfold within and across these layers is indicated by the arrow on the right side of the figure. The unidirectional arrows indicate the downstream influence of key causal forces across the levels of the hierarchy, and the bidirectional arrows indicate the interacting and interrelated causal nature of these forces both within and across levels.
      Figure 1
      Figure 1Conceptual framework of endemic firearm homicide syndemic.
      In this conceptual framework, endemic vulnerabilities are shaped by the aforementioned macrostructural and historical forces and policies
      • Sanchez C
      • Jaguan D
      • Shaikh S
      • McKenney M
      • Elkbuli A.
      A systematic review of the causes and prevention strategies in reducing gun violence in the United States.
      that induce downstream firearm violence and related afflictions: structural racism and discrimination,
      • Wilson WJ.
      The Truly Disadvantaged: The Inner City, the Underclass, and Public Policy.
      ,
      • Wong B
      • Bernstein S
      • Jay J
      • Siegel M.
      Differences in racial disparities in firearm homicide across cities: the role of racial residential segregation and gaps in structural disadvantage.
      inequitable health/healthcare policies,
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,
      • Formica MK
      • Rajan S
      • Simons N.
      Healthcare indicators and firearm homicide: an ecologic study.
      and liberal firearm access/ownership policies.
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      These macrostructural forces in turn induce environmental and social policies and forces, such as neighborhood disinvestment and socioeconomic inequality,
      • Wong B
      • Bernstein S
      • Jay J
      • Siegel M.
      Differences in racial disparities in firearm homicide across cities: the role of racial residential segregation and gaps in structural disadvantage.
      ,
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      inadequate healthcare access/quality,
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      and community access to firearms.

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      Multilayered policies and forces then play out at the individual level by shaping exposures and resources related to firearm violence risk among perpetrators and victims, including household economic deprivation and vulnerability (e.g., unemployment),
      • Choi KR
      • Saadi A
      • Takada S
      • et al.
      Longitudinal associations between healthcare resources, policy, and firearm-related suicide and homicide from 2012 to 2016.
      ,
      • Hohl BC
      • Wiley S
      • Wiebe DJ
      • Culyba AJ
      • Drake R
      • Branas CC.
      Association of drug and alcohol use with adolescent firearm homicide at individual, family, and neighborhood levels.
      healthcare deprivation (e.g., poor mental illness monitoring),
      • Botelho M
      • Gonçalves RA.
      Why do people kill? A critical review of the literature on factors associated with homicide.
      and greater individual firearm ownership.
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      Altogether, these upstream forces induce the array of mutually reinforcing afflictions at the firearm violence syndemicity level (as depicted using blue bidirectional arrows), including mental and behavioral antecedents for violence (e.g., mental illness, gang membership, domestic violence),
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      • Sanchez C
      • Jaguan D
      • Shaikh S
      • McKenney M
      • Elkbuli A.
      A systematic review of the causes and prevention strategies in reducing gun violence in the United States.
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      ,
      • Hohl BC
      • Wiley S
      • Wiebe DJ
      • Culyba AJ
      • Drake R
      • Branas CC.
      Association of drug and alcohol use with adolescent firearm homicide at individual, family, and neighborhood levels.
      inadequate resources for firearm injury treatment and recovery (e.g., lack of long-term mental and physical care for gunshot wound survivors),
      • Vella MA
      • Warshauer A
      • Tortorello G
      • et al.
      Long-term functional, psychological, emotional, and social outcomes in survivors of firearm injuries.
      and the likelihood of a firearm being present during violence
      • Wintemute GJ.
      The epidemiology of firearm violence in the twenty-first century United States.
      ,

      Semenza DC, Stansfield R, Link NW. The dynamics of race, place, and homicide context in the relationship between firearm dealers and gun violence. Justice Q. In press. Online January 31, 2020. https://doi.org/10.1080/07418825.2019.1707858.

      that manifest as firearm violence clusters within those populations and geographies in which these afflictions co-occur. These forces are also interacting and interrelated within levels; for example, at the Environmental and Social Forces and Policies level, neighborhood disinvestment and socioeconomic inequality can exacerbate issues with inadequate healthcare access/quality
      • Ryvicker M
      • Sridharan S.
      Neighborhood environment and disparities in health care access among urban Medicare beneficiaries with diabetes: a retrospective cohort study.
      and can impact community access to firearms.
      • Xu Y
      • Owusu-Agyemang S.
      Gun-related crime in Detroit, Michigan: exploring the spatial context of licensed firearm availability and neighborhood characteristics.
      Finally, mutual and reinforcing firearm violence afflictions may perpetuate extant firearm violence clusters through their influence on upstream and other macrostructural forces and policies (as indicated by red unidirectional arrows). For example, higher levels of firearm violence have been shown to deteriorate the economic health of communities through upstream mechanisms by reducing the growth of businesses and slowing home value appreciation,
      • Irvin-Erickson Y
      • Lynch M
      • Gurvis A
      • Mohr E
      • Bai B.
      Gun Violence Affects the Economic Health of Communities.
      thereby perpetuating and accelerating socioeconomic inequality in those communities with firearm violence syndemicity.

      Firearm Violence as a Novel Syndemic: Emerging Macrostructural Drivers and Downstream Impacts

      Novel vulnerabilities emerge over time and may be triggered by events such as national emergencies
      • Abdallah HO
      • Zhao C
      • Kaufman E
      • et al.
      Increased firearm injury during the COVID-19 pandemic: a hidden urban burden.
      and epidemics (e.g., the crack cocaine epidemic).
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      These events result in major societal disruptions that increase firearm violence and disparities through their exacerbatory impacts on endemic dynamically complex causal mechanisms.
      • Haviland MJ
      • Rowhani-Rahbar A
      • Rivara FP.
      Age, period and cohort effects in firearm homicide and suicide in the USA, 1983-2017.
      ,
      • Abdallah HO
      • Zhao C
      • Kaufman E
      • et al.
      Increased firearm injury during the COVID-19 pandemic: a hidden urban burden.
      For example, the COVID-19 pandemic has rapidly triggered a series of changes in macrostructural forces and policies that may have worsened endemic firearm violence vulnerabilities and induced novel vulnerabilities.
      • Caputi TL
      • Ayers JW
      • Dredze M
      • Suplina N
      • Burd-Sharps S.
      Collateral crises of gun preparation and the COVID-19 pandemic: infodemiology study.
      Thus, the aforementioned endemic firearm violence syndemic may be continually shaped, reinforced, and even exacerbated by such emerging phenomena and corresponding policy responses, therefore constituting a novel firearm violence syndemic that is demonstrative of the dynamic nature of firearm violence syndemicity.
      In Figure 2, emerging macrostructural drivers that correspond to the 3 reciprocal, dynamically complex causal mechanisms from Figure 1 (structural racism/discrimination, health care, and firearm access/ownership) are presented to show how they may exacerbate the endemic firearm violence syndemic and introduce novel syndemicity. First, policies such as stay-at-home/shelter-in-place orders that have shifted work organization toward remote work have been less applicable to low-income and racial/ethnic minority workers, who tend to work in essential occupations.
      • Raifman MA
      • Raifman JR.
      Disparities in the population at risk of severe illness from COVID-19 by race/ethnicity and income.
      Second, COVID-19 healthcare policies implemented in response to the pandemic have been shown to exacerbate existing inequities in healthcare access/quality.
      • Kim EJ
      • Marrast L
      • Conigliaro J.
      COVID-19: magnifying the effect of health disparities.
      Third, economic policies during the COVID-19 pandemic have determined firearm retailers to be essential businesses, thereby ensuring continued community-level firearm access, and other COVID-19 policies (e.g., stay-at-home orders) have been associated with increases in firearm violence.
      • Donnelly MR
      • Grigorian A
      • Inaba K
      • et al.
      A dual pandemic: the influence of coronavirus disease 2019 on trends and types of firearm violence in California, Ohio and the United States.
      Finally, those interacting afflictions caused or exacerbated by novel policies and forces triggered by the COVID-19 pandemic may reinforce inequitable structural and historical policies and forces.
      Figure 2
      Figure 2Conceptual framework of novel firearm homicide syndemic.

      Leveraging Syndemic Theory to Transform Firearm Violence Prevention

      Viewing firearm violence disparities through a syndemic lens can provide holistic, complex systems–informed insights about syndemogenesis—the development and exacerbation of syndemic interactions.
      • Singer M
      • Bulled N
      • Ostrach B
      • Mendenhall E.
      Syndemics and the biosocial conception of health.
      This knowledge can then lead to holistic, syndemic-informed preventive solutions that simultaneously address macro-level forces that lead to the clustering of afflictions, as well as co-occurring and interacting afflictions at the individual level.
      • Singer M
      • Bulled N
      • Ostrach B
      • Mendenhall E.
      Syndemics and the biosocial conception of health.
      For example, syndemic-informed prevention targeting the dynamically complex causal mechanism centered on firearm access/ownership from Figures 1 and 2 may simultaneously reform federal firearm laws and enhance street-level enforcement of corresponding laws to ensure legal firearm ownership. Further, syndemic perspectives can be integrated into existing evidence-based firearm violence prevention programs, such as those focused on street outreach (e.g., Cure Violence),
      • Butts JA
      • Roman CG
      • Bostwick L
      • Porter JR.
      Cure violence: a public health model to reduce gun violence.
      greening (e.g., Clean & Green),
      • Heinze JE
      • Krusky-Morey A
      • Vagi KJ
      • et al.
      Busy streets theory: the effects of community-engaged greening on violence.
      and hospital-based interventions,
      • Juillard C
      • Cooperman L
      • Allen I
      • et al.
      A decade of hospital-based violence intervention: benefits and shortcomings.
      by emphasizing macro-level forces and policies that are not currently addressed. More broadly, syndemic-informed prevention may generate countersyndemics, which represent high-leverage intervention opportunities where the targeted change to one vulnerability or affliction can nonlinearly protect against firearm violence and other mutually reinforcing afflictions.
      • Singer M
      • Bulled N
      • Ostrach B
      • Mendenhall E.
      Syndemics and the biosocial conception of health.
      An example of a potential countersyndemic may be targeting healthcare access and quality, such as through macro-level healthcare reform, which could then simultaneously address multiple syndemic afflictions—namely, the prevalence of mental/behavioral antecedents of violence (e.g., by improving access/availability of mental health resources) and insufficient resources for gunshot wound treatment/recovery (e.g., by improving access to trauma centers).

      MOVING FORWARD: INTEGRATING COMPLEX SYSTEMS APPROACHES AND SYNDEMIC THEORY INTO GUN VIOLENCE RESEARCH AND PREVENTION

      Engaging in novel, syndemic-grounded gun violence research and prevention is possible through methodologies already commonly used in the field, such as cross-sectional
      • Thurston IB
      • Howell KH
      • Kamody RC
      • Maclin-Akinyemi C
      • Mandell J.
      Resilience as a moderator between syndemics and depression in mothers living with HIV.
      and longitudinal
      • Pitpitan EV
      • Kalichman SC
      • Eaton LA
      • et al.
      Co-occurring psychosocial problems and HIV risk among women attending drinking venues in a South African township: a syndemic approach.
      designs and geospatial modeling,
      • Islam N
      • Lacey B
      • Shabnam S
      • et al.
      Social inequality and the syndemic of chronic disease and COVID-19: county-level analysis in the USA.
      and analytical techniques, such as linear modeling.
      • Tsai AC
      • Venkataramani AS.
      Syndemics and health disparities: a methodological note.
      However, an array of methodologic and analytical approaches, collectively referred to as computational modeling and simulation techniques, are specifically tailored for engaging in complex systems science. Within the firearm violence literature, computational modeling and simulation techniques, such as system dynamics modeling,
      • Bridgewater K
      • Peterson S
      • McDevitt J
      • et al.
      A community-based systems learning approach to understanding youth violence in Boston.
      agent-based modeling,
      • Castillo-Carniglia A
      • Pear VA
      • Tracy M
      • Keyes KM
      • Cerdá M.
      Limiting alcohol outlet density to prevent alcohol use and violence: estimating policy interventions through agent-based modeling.
      and network analysis,
      • Green B
      • Horel T
      • Papachristos AV.
      Modeling contagion through social networks to explain and predict gunshot violence in Chicago, 2006 to 2014.
      have been used in this and related domains. Further, these techniques have been successfully used in syndemic-grounded research
      • Homer J
      • Milstein B.
      Communities with multiple afflictions: a system dynamics approach to the study and prevention of syndemics.
      • Morshed AB
      • Kasman M
      • Heuberger B
      • Hammond RA
      • Hovmand PS.
      A systematic review of system dynamics and agent-based obesity models: evaluating obesity as part of the global syndemic.
      • Choi KW
      • Smit JA
      • Coleman JN
      • et al.
      Mapping a syndemic of psychosocial risks during pregnancy using network analysis.
      and thus could be extended to explore firearm violence syndemicity and identify syndemic-informed preventive solutions.
      As a final note, the integration of complex systems and syndemic approaches advocated for in this manuscript should not be understood as a replacement for current empirical work. Instead, they should be viewed as alternative approaches that, when combined, can be complementary and, in fact, can be synergistic. In particular, the development and validation of computational modeling and simulation techniques typically rely on inference drawn from an array of studies grounded in the current risk factor paradigm. In this way, these models meaningfully integrate known science by putting the pieces together into holistic, complex systems–grounded empirical frameworks, thereby harnessing the strengths of both.

      CONCLUSIONS

      The persistent and inequitable clustering of firearm violence within specific communities and populations and the inherent limitations of the dominant research paradigm indicate the need to consider novel approaches to research and prevention. Complex systems approaches may facilitate an understanding of the dynamically complex causal mechanisms that generate and perpetuate the disproportionate distribution of firearm violence. Syndemic theory may represent a powerful, complex systems–grounded theoretical framework for holistically conceptualizing how firearm violence and associated reinforcing afflictions nonlinearly emerge from endemic and novel vulnerabilities that are shaped by structural and historical policies and forces. These theoretical insights may then inform high-leverage, syndemic-informed prevention strategies.

      ACKNOWLEDGMENTS

      No financial disclosures were reported by the authors of this paper.

      CRediT AUTHOR STATEMENT

      Michael K. Lemke: Conceptualization; Visualization; Writing-original draft; Writing-review and editing. Dwayne A. Wolf: Conceptualization; Writing-review and editing. Stacy A. Drake: Conceptualization; Writing-review and editing.

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