Firearm homicide is one of the most devastating events to impact not only individuals but entire communities. In the United States (U.S.), between 2010 and 2020, firearm homicide prematurely ended the lives of >150,000 people, including approximately 9400 young people under the age of 18 (Centers for Disease Control and Prevention, 2022). Like nearly all poor health outcomes in the U.S., the burden of firearm homicide is not evenly distributed; rather, it is endured disproportionately by minoritized and marginalized communities. Latinx children and teens experience firearm homicide at 3 times the rate of their white counterparts. It is the 2nd leading cause of death for Black girls and women ages 15–24 and has been the leading cause of death for Black boys and men ages 15–24 for over 30 years (Centers for Disease Control and Prevention, 2022). The inequitable distribution of community firearm violence and, by extension, its myriad social and health repercussions, is a catastrophic yet predictable outcome of decades of structural racism, state-sanctioned violence, and disinvestment in institutions in racially and economically segregated neighborhoods that are critical to health and safety.

Homicide is arguably the most disastrous outcome of firearm violence, but it is the tip of the iceberg. Nonfatal firearm injuries occur up to 4 times as frequently as homicide (Hipple et al., 2020; Kaufman et al., 2021), and studies find anywhere from 13% to 65% of young people report hearing gunshots or witnessing someone get shot or shot at in their lifetimes (Bancalari et al., 2022; Finkelhor et al., 2015; Fitzpatrick, 1997; Stein et al., 2003; Turner et al., 2019; Zimmerman and Posick, 2016). Community violence exposure is associated with a host of emotional and behavioral problems, including posttraumatic stress symptoms, anxiety, and depression (e.g., Ahern et al., 2018; Berman et al., 2021; Foell et al., 2021; Gaylord-Harden et al., 2011; Gorman-Smith and Tolan, 1998), particularly when firearms are involved (Aubel et al., 2021; Fowler et al., 2009; Kagawa et al., 2020; Opara et al., 2020; Ranney et al., 2019; Rowhani-Rahbar et al., 2019). Whereas the majority of these studies define “exposure” as being a victim, perpetrator, or witness to violence (Cimolai et al., 2021; Mitchell et al., 2021; Shulman et al., 2021; Spano and Bolland, 2013; Turner et al., 2019), the impacts of firearm violence can also affect others in the community, regardless of direct or witnessed experience.

Broader exposure to spatially proximate firearm violence – any incident that occurs near where someone lives or spends time – is both widespread and uneven, further reflecting structural inequities that disproportionately disadvantage and compromise the health and well-being of Black and Latinx youth. One study found 56% of Black youth and nearly half of Latinx youth in large U.S. cities live within 1300 m (approximately 0.8 miles) of a past-year firearm homicide occurrence, with 1 in 4 Black youth and 1 in 5 Latinx youth experiencing 3 or more incidents; comparable percentages for white youth were 17% for any incident and <1% for 3 or more (Kravitz-Wirtz et al., 2022). In a separate analysis using the same dataset, Black and Latinx youth in middle-to-high income households were nearly twice as likely as white youth in low-income households to live or attend school near a deadly firearm violence incident (James et al., 2021). These incidents of spatially proximate firearm violence can become salient in youths' daily lives via numerous sources, including learning about an incident from peers, family members, or media; hearing or seeing police, ambulances, or crime scenes; or passing memorials or vigils where violent deaths have occurred (Wintemute et al., 2022).

A small but growing number of studies have investigated associations between spatially proximate firearm violence exposure and youth mental health outcomes. One study found an increase in emergency department utilization for mental health-related symptoms among children in the days following a firearm violence incident occurring within a few blocks of their homes (Vasan et al., 2021). Another study found that every additional exposure to a deadly firearm violence incident near a child's home in the past year increased behavioral problems by nearly 8%, even after accounting for socioeconomic indicators and area-level crime (Gard et al., 2022). However, few published studies have specifically explored the effects of spatially proximate firearm violence exposure on anxiety and depression among young people, and even fewer have analyzed potential variation in those effects. One study of juvenile system-involved adolescent males found that recent exposure to firearm violence (experienced or witnessed a shooting) was associated with increased levels of aggression and anxiety, with less support for increased depression (Shulman et al., 2021). Another study found that the occurrence of a past-year firearm homicide within 1 mile of an adolescent's home or school was associated with significantly worse symptoms of anxiety and depression for girls but only marginally worse symptoms of anxiety for boys (Leibbrand et al., 2020).

When researchers have explored heterogeneity in the effects of spatially proximate firearm violence exposure on youths' mental health, they have typically focused on variations by gender and race/ethnicity, rather than also considering modifiable social determinants that could additionally affect the exposure-outcome relationship, such as neighborhood disadvantage or prevalence of community violence. As a result, much remains unknown about whether the impacts of spatially proximate firearm violence exposure on youths' mental health vary by the same community-level characteristics that shape youths' risks of experiencing that exposure in the first place, and what risk and protective factors may underlie such variation. It is possible that further stratification may reveal heterogeneous effects in this relationship, suggesting that more tailored interventions are necessary to most effectively address mental health-related harms related to firearm violence exposure.

This study expands existing literature on the association between spatially proximate firearm violence exposure and youths' mental health outcomes – specifically, anxiety and depression –by examining average and heterogeneous effects using quasi-experimental methods. We use a rich, longitudinal dataset that allows for the inclusion of a comprehensive array of individual, familial, and neighborhood-level characteristics that contribute to systematic differences in youths' probability of spatially proximate firearm violence exposure. In turn, we employ propensity score matching methods to approximate causal effects of such exposure on youths' anxiety and depression symptoms. Further stratifying by youths' propensity of exposure helps address theoretical debates about the role of firearm violence exposure as an acute stressor among youth with relatively low risks of exposure or one of many cascading chronic stressors among youth with relatively high risks of exposure. Consequently, we shed light on the ways youths' risks of exposure to spatially proximate firearm violence may also shape their varying responses to such exposure. This approach can also suggest malleable social-ecological factors that may increase youths' vulnerability or resilience to the effects of exposure, offering important insights for the development of focused strategies to disrupt cycles of violence and trauma.

This study investigated the average and heterogeneous associations of spatially proximate, past-year firearm homicide exposure with anxiety and depression symptoms among relatively socioeconomically disadvantaged youth in large U.S. cities (Reichman et al., 2001). Given that structural and economic inequities correlate with elevated levels of firearm violence, these youth are also at a higher risk of exposure. Yet we found that even among this population, the effects of firearm homicide exposure were not evenly distributed. Using propensity score matching, we found a statistically significant average association between spatially proximate firearm homicide exposure and symptoms of depression among youth. However, heterogeneous effects analyses yielded evidence that this average association was driven by youth, and particularly boys, who were the most disadvantaged and had the highest risk of firearm homicide exposure; no statistically significant effects were observed for youth at relatively lower risks of exposure. This finding suggests that the accumulation of stressors associated with structural disadvantage, coupled with exposure to firearm violence, may make boys and young men uniquely vulnerable to the mental health impacts of such exposure. When considered alongside research showing that youth experiencing more complex adversity histories may be more susceptible to indirect firearm violence exposure, and that youth with a higher sense of safety are less likely to experience extreme sadness following exposure (Mitchell et al., 2021), our findings underscore the urgent need to implement and adequately fund community-based violence interventions, including but not limited to Advance Peace (Corburn et al., 2021; Corburn et al., 2022), Becoming a Man (Prochaska, 2013), and hospital-based violence interventions (Wical et al., 2020) that simultaneously offer young people access to mental health and coping support while also notably reducing all forms of community firearm violence. Our findings also point to the need for tailored interventions aimed at identifying and engaging youth at greatest risk of firearm violence exposure in affordable, accessible, and culturally-responsive mental health support services in their schools and communities. Furthermore, they highlight the harm to these vulnerable populations exacerbated by our societal failure to redress persistent structural inequities, including concentrated disadvantage, structural racism, and concentrated risk of firearm violence exposure, that can have devastating effects on physical and mental health and well-being.

Our findings specific to Black boys are notable and deserve further comment. In the boys-only analyses, those with the highest risk of exposure were overwhelmingly Black; in fact, there were no Black boys in either of the two lower risk strata. The finding that spatially proximate firearm homicide exposure was significantly associated with depression only among boys in the stratum with the highest exposure risk underscores both the disturbingly high risk of community firearm violence exposure among Black boys in the U.S. and the devastating toll that exposure can have on their mental health. While a number of researchers have examined the relationship between community violence exposure and adverse mental health consequences among Black boys (e. g., Gaylord-Harden et al., 2016; Gorman-Smith and Tolan, 1998; Lambert et al., 2021), findings have been inconsistent, with some detecting an association and others not. However, few have isolated the impact of deadly firearm violence exposure, which may have more harmful consequences on the mental health of youth and on socioeconomically disadvantaged Black boys in particular. This is a critical area of future study. Black boys in the U.S. currently lack easily accessible interventions for addressing poor mental health outcomes such as depression, anxiety, substance use disorders, and posttraumatic stress disorder symptoms like hypervigilance and emotional detachment, yet they endure distinct stressors related to racial discrimination, increased risk of state surveillance, contact and violence, and increased exposure to community firearm violence (Burrell et al., 2021). They also face particular barriers associated with receiving appropriate care even when they have access to mental health professionals; numerous researchers have noted concerns regarding overdiagnosis, underdiagnosis, and decreased likelihood of psychiatric treatment for African-American youth, as well as the likely role this misaligned care plays in fueling disparities in Black youth rates of school suspensions, expulsions, and contact with the juvenile and criminal legal systems (Baglivio et al., 2017; Holden et al., 2012; Liang et al., 2016; Marrast et al., 2016).

Furthermore, while outside the scope of the current study, we cannot ignore the necessity for more research examining any relationship between community firearm violence exposure and the alarming and unprecedented rise in firearm suicide among Black youth over the past 20 years (Sheftall et al., 2022). Scholars have noted that among Black youth, knowledge of family and peers' community violence exposure is associated with subsequent increases in suicide ideation (Lambert et al., 2021), further accentuating the need for more research to better understand these associations, especially those related to firearm-specific violence exposure.

As supported by our ancillary findings, protective factors and interventions for Black youth exposed to community violence include strengthening social ties and cohesiveness between youth and their formal or surrogate caregivers (Hammack et al., 2004), increasing social support, lowering social constraints for discussing violence, and increasing connectedness with teachers in school (Ozer and Weinstein, 2004). Future research and practice should consider whether interventions prioritizing these domains may help mitigate the negative mental health impacts of firearm-specific violence exposure. However, we must not further delay implementing culturally-affirming and healing-centered responses to community firearm violence and its mental health sequalae for Black youth (particularly boys) with chronic exposure. Trusted and credible community leaders and peers could be trained on violence intervention and therapeutic modalities suitable and acceptable to Black youth and their families, and parents and teachers could be educated on strategies that strengthen their connections and cohesiveness with Black youth in their lives. Furthermore, data on community firearm violence could be leveraged to identify and deliver therapeutic services in near-real time to the youth who may need it most.

Neither the average nor heterogeneous effects analyses yielded statistically significant relationships between firearm homicide exposure and anxiety, although the direction and magnitude of the estimates in the full-sample and girls-only analyses suggest a possible association may be observed with a larger pool of youth. Using the same dataset as in this study, but without propensity score matching, Leibbrand et al. (2020) found evidence that spatially proximate firearm homicide exposure is significantly associated with anxiety and depression among girls but not boys. When the researchers applied survey weights in supplementary analyses, anxiety and depression were no longer significantly associated with the exposure among girls, yet depression became significant among boys. While our propensity score matching approach helps address sampling design limitations and the differential likelihood of community violence exposure, the stratification method constrained the within-stratum sample size and power available for analyses. Thus, though we did not observe a significant association between spatially proximate deadly firearm violence exposure and anxiety, we have reason to believe that a true association may still exist. Future examinations of this relationship utilizing larger datasets should also incorporate exposure to spatially proximate nonfatal firearm violence, given the higher frequency of nonfatal (versus fatal) firearm injuries in the U. S.

While the results from our ancillary analyses of potential moderators were hypothesis-generating, rather than hypothesis-testing, they offer additional insights into interesting areas for future exploration. In the full-sample and boys-only analyses, youth at high risk of exposure to spatially proximate firearm homicide and who were indeed exposed had higher prevalence of experiences with police stops and unjust treatment by police than their counterparts with similar risk of firearm homicide exposure but who were not exposed. The fact that these young people were more likely to have witnessed police stops is not surprising on its own, given that they also lived or attended school near a past-year deadly firearm homicide incident. However, the increased risk for experiencing depression following the exposure, coupled with the increased probability of police contact, may warrant additional analysis. Studies have shown that youth of color are more likely than white youth to experience emotional distress during witnessed police stops (Jackson et al., 2021), and that persistent police contact has adverse mental health outcomes for Black youth (Jindal et al., 2022). Research has also found that youth reporting personal or vicarious police stops have worse self-reported health than those with no police contact, and that perceived procedural injustice by the police exacerbates the association between police contact and self-reported health (McFarland et al., 2019). Taking our findings together with existing research, it is recommended that interventions aiming to reduce community firearm violence exposure while simultaneously reducing youth contact with police, especially in areas of high disadvantage and high risk of exposure, receive greater attention and consideration.

We also observed a potential moderating effect of extracurricular and community involvement on the association between firearm homicide exposure and depression for boys with the highest risk of exposure, with those exposed to firearm violence having marginally higher extracurricular and community involvement than those who were unexposed. It is possible that boys with greater extracurricular and community involvement are most affected when firearm homicide occurs within their communities, as they may be more likely to have social ties to the victim or connection to community. Alternatively, it is possible that despite their involvement in extracurricular and community activities, boys living in these highly vulnerable environments are at remarkably higher risk of depression when firearm violence occurs. Again, though, as this was not a formal test for moderation, these results are merely suggestive of possible future areas of investigation.

This study furthers research on the impacts of community firearm violence exposure on youths' mental health and provides added support for examining both average and heterogeneous effects of such exposure. We illustrate the importance of conceptualizing community firearm violence exposure beyond direct or witnessed experience to account for the broader mental health-related harms felt by those who live and learn in neighborhoods where firearm violence occurs. Our results suggest that youth most at risk for spatially proximate firearm violence exposure, and particularly boys and young men, are in great need of intervention and prevention efforts that dually work to reduce exposure to community firearm violence while mitigating its mental health consequences.