research paper on mass shootings

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Advancing Mass Shooting Research To Inform Practice

Few events in American life evoke stronger reactions across society than mass shootings. They are part of the broader phenomenon of mass violence that includes, for example, terrorist attacks and war-related events. But mass shootings are distinguishable from those categories of mass violence in that their underlying motive sometimes appears to be unknown. Typically, mass shootings occur in a public place, with a single shooter, and most victims are killed or wounded indiscriminately. [1]

Because mass shootings have a severe impact on victims and society, they are a national criminal justice priority. As the frequency of mass shootings has increased in recent years, law enforcement and researchers have intensified their efforts to understand and prevent this form of firearms violence. [2] But their efforts are being held back by two systemic deficiencies: (1) the absence of a uniform definition of mass shootings and related concepts and (2) the absence of consistent databases that gather, sort, and share essential facts on attempted and completed mass shooting incidents.

In an effort to improve understanding of mass shootings, NIJ science staff carried out a systematic literature review to identify the current state of knowledge suitable for use in preventing these incidents. They uncovered apparent inconsistencies in researchers’ definitions of mass shooting incidents. Moreover, they found that the analyses supporting the definitions often rely on open-source data that are unreliable, inconsistent, or both. [3] These inconsistencies may lead to mixed — or even contradictory — findings, suggesting a need to align data and definitions in a more unified, coherent approach.

NIJ also convened leading researchers and law enforcement practitioners to gain additional insight into the challenges surrounding mass shooting studies and prevention strategies. The experts offered recommendations on how the field should move forward to advance both the research on and the prevention of mass shootings. All of these insights will help guide NIJ’s leadership of mass shooting research and data management going forward, as key elements of its larger role in directing scientific investment to address violent crime and inform prevention efforts.

Inconsistencies in Definitions

To better understand the state of knowledge and identify gaps in research on mass shootings, NIJ science staff systematically reviewed the literature from 1997 through 2016. [4] Their analysis encompassed 44 research studies on mass shootings. Results revealed both consistencies and inconsistencies in the literature. Collectively, studies have yielded a number of high-utility insights on shooter characteristics, choice of targets, weapons, and other variables. Generally, however, the scholarship has been hampered by a lack of agreement on definitions of critical terms, such as “mass shootings” and “mass murders,” and by the absence of consistent sources of data on mass shootings.

The literature does not define “mass shooting” consistently, or even in similar contexts. The federal criminal code lacks a distinct mass shooting offense; this may help explain why researchers use different terminology, or types of criminal offense, in their analyses of the same phenomenon. [5]

Among the 44 studies analyzed, the most common definition of a mass shooting is an incident in which four or more victims are killed with a firearm in a public place (48%). Several studies defined the offense as an event during which as few as two (5%) or three (9%) victims are killed, whereas more than one-third of the studies more broadly defined the term as an incident in which multiple victims are killed (38%). Others either defined a mass shooting incident as having a minimum of five victims or did not specify a victim threshold.

The definitions in the analyzed studies include incidents that take place in publicly accessible spaces such as schools, workplaces, places of worship, and businesses. The incidents are also defined as a single, continuous event within a short time frame, but the specific time frame can vary. The definitions often exclude ideologically motivated terrorist acts as well as gang, drug, and other shooting incidents that resulted primarily from the commission of other crimes, such as aggravated robbery, familicides, and domestic violence. Some of these studies, however, do not specify whether certain types of offenses were excluded from the definition.

This lack of consistency in defining mass shooting events is reflected in contradictory findings across a number of studies. The differences noted appear to contribute to varying conclusions about individuals’ average age, motives, personality, suicidality, and target selection (i.e., victim, or victims, and place). Other notable differences in findings relate to the choice of firearms as well as the possible influence of news media coverage on mass shooting events and those who commit them. Importantly, wide variability in mass shooting definitions — in terms of the requisite minimum numbers of individuals shot and killed — casts serious doubt over the field’s ability to accurately capture all of the cases and analyze trends.

Limited Access to Consistent Databases

Compounding the problem is the lack of uniform, reliable data sources. The literature reviewed used 10 types of data sources, and the majority of the studies used more than one type of data source. Of the 122 distinct data sources used in the 44 studies, 65% came from secondary, open-source data. Open-source data refers to publicly available and accessible information such as databases, news and media accounts, or other widely available sources. Thirty-three percent came from official records that are publicly accessible for the most part, and 2% came from interviews ( see exhibit 1 ).

It is evident that there is no single, primary source of data used across the research on mass shootings. Some of the official records, such as the FBI’s Uniform Crime Reports, Supplementary Homicide Reports, and National Incident-Based Reporting System, are often based on case files developed for the purposes of investigation and prosecution. Many times, however, they lack information on a wide range of variables that could advance prevention research. Such limitations often lead researchers to supplement the data with information from open sources or to rely solely on secondary data. Moreover, even if those standard, official reports were factually rich and complete, it is highly unlikely that they would be able to address many of the questions that are relevant to informing practices around preventing mass violence. For example, they generally do not include data on what the shooter did to prepare for the shooting, whether the shooter expressed some form of grievance, or whether the shooter had a history of mental health issues or had experienced a recent loss.

The factual limitations of official reports complicate the task of assessing the reliability of sources, raising questions such as how each data source defines the phenomenon, what specific information the source provides, and — in the case of databases — what the time frame is for including events. As with inconsistencies in the definition of mass shootings in terms of the number of victims killed, the use of different data sources obfuscates trends and the impact of policies. This is not to say that no study has produced valuable results and recommendations. But without a thorough analysis of the research design by a trained eye, the end users of research, such as policymakers and practitioners, may arrive at conclusions that are erroneous and that may produce more harm than good.

There are a number of ongoing efforts by researchers and the federal government to build or enhance mass shooting databases. However, the research community must identify the challenges in this line of research and determine a set of characteristics that would make any given mass shooting database more reliable and useful in informing prevention.

Heeding the Experts

In the latter half of 2018, NIJ held directed discussions with subject matter expert groups of law enforcement officials and scholars as part of its initiative to assess existing mass shooting research and gauge its shortcomings. Insights gained at those sessions can inform and refine research going forward.

The primary objectives were to:

• Assess the need for uniform definitions in mass shooting data collection and analysis.
• Discuss the benefits of establishing data collection techniques to consistently catalog all of the pertinent mass shooting information.

Law enforcement discussants (practitioners) were current and former members of federal and local law enforcement agencies. Researcher discussants (researchers) were a multidisciplinary collection of scientists from several U.S. universities.

Points of Broad Agreement

The practitioners and researchers agreed on certain discrete research and practice needs. For example, they reached general agreement that a universal definition of mass shootings would not solve all ambiguity problems but would be an important first step. A common definition of mass shooting should be broad but not tied to any fixed minimum number of victims (for instance, a rule that a mass shooting means the killing, by firearm, of four or more people). Some samples of relevant comments by discussants include:

• Researcher: “The number of people killed can be happenstance. … If you focus too much on [a] happenstance outcome, things might get lost. It seems arbitrary to say three or four or five victims minimum. That seems to be missing the big picture.”
• Practitioner: “That number [four] seems arbitrary. It should have less to do with efficiency, [that is, the] number of people in the room, etc., than the intent of the offender.”
• Practitioner: “You have to include nonfatal injuries. They all intend to kill, but if they are a poor shooter, you still have the same dynamics and personality — they just didn’t know how to operate the weapon.”

They also agreed that a mass shooting event is an incident where there is an evident premeditated intent to shoot to kill, regardless of the number of actual fatalities or injuries.

• Researcher: “But with the definition, I think we can discern that what we’re trying to get at is this event with this person who had the intent to kill large numbers of people.”
• Practitioner: “I think numbers are arbitrary and don’t matter. If the intent was to kill a bunch of people, it doesn’t matter. It would be counterproductive for prevention to exclude them.”
• Practitioner: “So, we get to the intent of the individual when they came to the incident. If they did [intend harm to a lot of people], it’s in; if not, it’s out. The reality is that if you include cases with only two or more victims, the offender in those cases might have been trying to kill more but didn’t.”

Points of Difference

On other issues, there was notable divergence between the practitioners and researchers. For one, practitioners tended to favor reliance on data and data sources that are objective and verifiable, whereas researchers tended to be more receptive to open sources as well as more subjective data related to, for instance, health factors. Key examples of where practitioners and researchers diverged include desired data sources for mass shootings and the time range for including an incident.

It is important to note that different data sources are designed for different purposes. Official data sources are often developed for investigations and prosecutions. Such sources have high value for answering some investigative questions, but may not be at all responsive to others. Official sources tend to focus on proximal factors related to the crime (e.g., time, place, manner, demographics, and other information that describes the criminal act and the individual committing it). On the other hand, media accounts (an example of an open source) are more likely to trace back further in time and look more broadly at other possible factors that influenced the individual committing the crime. That is, they may include information that is absent from official sources but is valuable for prevention purposes. At the same time, compared with official records, media sources may be more influenced by subjective judgments and errors.

Researchers tended to support a research approach that includes open-source data, such as media accounts. Several researchers said that because of a lack of access to official records and sensitive data, they often relied on open sources to fill the gaps and triangulate data. It should be noted that, if given the choice, these researchers said they would prefer to use official data sources. But they also see the value of triangulating information from multiple types of data sources for research purposes.

Practitioners tended to be strongly opposed to an open-source approach and to reliance on media accounts. Several practitioners said that in their view, media accounts are largely unreliable as primary data sources on mass shootings.

The sharp divergence in views between researchers and practitioners on data source preferences may reflect the distinct nature of their respective professions. Practitioners in the law enforcement field are accustomed to using official data, and their interest in determining accountability and culpability for criminal acts is often best served by data attributable to official sources. Researchers tend to seek answers to a broader range of questions, calling for broader data sources.

Some researchers and a local-level practitioner said they valued the collection of retrospective data (e.g., from the preceding 50 years) on qualifying incidents that were not sourced from media reports. They also emphasized the importance of collecting the same kind of data prospectively. Some practitioners, on the other hand, recommended a focus on data from 2000 forward, given the limited access to information prior to the implementation of internet technology.

Recommendations for Future Research

A primary purpose of the expert discussion groups convened by NIJ was to produce guidance on developing further mass shooting studies to improve prevention. Researcher and law enforcement participants voiced support for a series of recommendations:

• Partner with law enforcement agencies (both local and federal) and associations to better access official data on mass shootings through sources that include interviews with incarcerated persons, police investigations, and mining of information on multiple-victim shooting incidents that were not covered in any depth by the media.
• Examine data on averted attacks.
• Compare mass shootings with other forms of mass violence.
• Help identify and debunk misconceptions with scientific evidence (e.g., weapon choice, mental health, motivation, planning and preparation).
• Estimate costs of mass shootings and victim impacts over time.
• Develop guidelines and resources for identifying and managing people of concern.
• Create an analytical model to enable practitioners to engage in predictive analysis of mass shootings. The model would be based on the time (including date), place, and modus operandi of studied mass shooting events.
• Create models for information exchange among local and federal stakeholders.

Moving Forward

NIJ’s analysis of mass shooting literature and its structured engagement of experts point to the advisability of certain major action items for mass shooting research and law enforcement practice. First, there appears to be broad sentiment in favor of moving away from a number-based system of rigidly defining mass shootings and related phenomena, and toward defining mass shootings more flexibly. An incident should not be entirely omitted from a mass shooting data set where, for example, a shooter with evident intent to kill multiple persons opens fire in a park where 10 individuals are present, with several resulting gunfire injuries but three or fewer fatalities.

Law enforcement should have a more active role in the study of mass shootings and in translating research to practice — for example, developing detection methods and tips and educating and training bystanders, school counselors, and others. Beyond an expanded research role, law enforcement officers will remain the last, crucial barrier between prospective shooters and their intended victims. Law enforcement must enhance its capability to detect and intercept mass shooters, and educate members of the public to detect and report any warning signs of prospective shooters in their communities, if the threat to society is to be reduced.

Criteria should be developed to facilitate adopting uniform definitions and data characteristics across all databases. NIJ recognizes that uniform, consistent cataloging of past mass shootings designed to support future data entry is an essential first step in advancing research and prevention efforts. Additionally, NIJ hopes to glean insights from analogous fields that study rare incidents (e.g., terrorism) to replicate and improve on established data collection methods and sustainability.

Preparedness for mass shootings — deeply traumatizing social phenomena as elusive as they are disruptive — will require an increasingly focused and coordinated effort by the research and practice communities as we move forward.

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Learn more about NIJ research awards on mass shootings .

About This Article

This article appears in  NIJ Journal issue 282.

[note 1] William J. Krouse and Daniel J. Richardson, “Mass Murder with Firearms: Incidents and Victims, 1999-2013,” Congressional Research Service , July 30, 2015.

[note 2] J. Pete Blair and Katherine W. Schweit, A Study of Active Shooter Incidents in the United States Between 2000 and 2013 , Washington, DC: Texas State University and Federal Bureau of Investigation, 2014; Federal Bureau of Investigation, Active Shooter Incidents in the United States in 2016 and 2017 , Washington, DC: Advanced Law Enforcement Rapid Response Training (ALERRT) Center at Texas State University and Federal Bureau of Investigation, 2018; Federal Bureau of Investigation, Active Shooter Incidents in the United States in 2018 , Washington, DC: ALERRT Center at Texas State University and Federal Bureau of Investigation, 2019; and Katherine W. Schweit, Active Shooter Incidents in the United States in 2014 and 2015 , Washington, DC: Federal Bureau of Investigation, 2016.

[note 3] Lin Huff-Corzine et al., “Shooting for Accuracy: Comparing Data Sources on Mass Murder,” Homicide Studies 18 no. 1 (2014): 105-124, doi:10.1177/1088767913512205.

[note 4] A synthesis of the literature published through 2016 was completed in preparation for the topical meetings with experts described in this article. Before this article was published, NIJ science staff reviewed subsequent mass shooting studies published from 2017 through July 2019 and found no discrepancies with previous research with respect to the definitional and database-related issues.

[note 5] On January 14, 2013, the 112th Congress amended the Investigative Assistance for Violent Crimes Act of 2012 (PL 112-265) to define the term “mass killings” as three or more killings in a single incident, and the term “place of public use” as it is defined under Section 2332f(e)(6) of Title 18, United States Code. The act does not specify the weapon used, nor does it account for injured victims.

About the author

Basia E. Lopez is an NIJ social science analyst. Danielle M. Crimmins is a graduate research assistant at NIJ. Paul A. Haskins is a social science writer and contractor with Leidos.

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Mental Illness, Mass Shootings, and the Future of Psychiatric Research into American Gun Violence

This article outlines a four-part strategy for future research in mental health and complementary disciplines that will broaden understanding of mass shootings and multi-victim gun homicides. First, researchers must abandon the starting assumption that acts of mass violence are driven primarily by diagnosable psychopathology in isolated “lone wolf” individuals. The destructive motivations must be situated, instead, within larger social structures and cultural scripts. Second, mental health professionals and scholars must carefully scrutinize any apparent correlation of violence with mental illness for evidence of racial bias in the official systems that define, measure, and record psychiatric diagnoses, as well as those that enforce laws and impose criminal justice sanctions. Third, to better understand the role of firearm access in the occurrence and lethality of mass shootings, research should be guided by an overarching framework that incorporates social, cultural, legal, and political, but also psychological, aspects of private gun ownership in the United States. Fourth, effective policies and interventions to reduce the incidence of mass shootings over time—and to prevent serious acts of violence more generally—will require an expanded body of well-funded interdisciplinary research that is informed and implemented through the sustained engagement of researchers with affected communities and other stakeholders in gun violence prevention. Emerging evidence that the coronavirus pandemic has produced a sharp increase both in civilian gun sales and in the social and psychological determinants of injurious behavior adds special urgency to this agenda.

Indiscriminate shooting rampages in public places accounted for approximately 0.5% of homicides in the United States in 2019, 1 , 2 yet an estimated 71% of adults experienced fear of mass shootings as “a significant source of stress in their lives,” causing 1 out of 3 people to avoid certain public places, according to a national survey by the American Psychological Association. 3 , 4 In their responses to heightened community concerns over the threat of mass shootings, numerous public officials in recent years have pointed to “mental illness” as a simplified explanation for these terrifying acts of violence. 5 The “deranged shooter” narrative resonates with a persistent (if largely false) belief among majorities of adults in the United States: the notion that people diagnosed with serious psychiatric disorders such as schizophrenia are likely or very likely to be violent. 6 This construction of the problem relies on an elastic and pejorative definition of mental illness and places psychiatrists in an often unwelcome yet strategic spotlight. 7

On the one hand, the public’s a priori definition of mass shooters as seriously mentally ill invites and reinforces unrealistic expectations that mental health experts should be able to predict and prevent acts of mass violence. It tends to inspire public support for restrictive policies and interventions targeting psychiatric patients. 6 On the other hand, the “deranged shooter” story can give mental health professionals a powerful voice and audience—people look to them for answers and solutions—which translates into opportunities to reframe the debate over what should actually be done about mass shootings in the United States.

What can psychiatrists and other mental health clinicians, researchers, and policy makers do to foster evidence-based solutions to prevent mass shootings, and to mitigate the population risk of firearm injuries in general, without adding to the burden of stigma and social rejection that people who are recovering from mental illnesses may feel when others assume they are dangerous?

Existing scientific evidence paints a complex—if incomplete—picture of the causes of mass shootings and other acts of serious violence. Until recently, a congressional ban on federal funding for most gun-related research has prevented scientists and scholars from conducting the full range of interdisciplinary studies that would provide a better understanding of the problem and point the way to effective solutions. 8

In what follows, we outline a four-part strategy for future research in mental health and complementary disciplines that will broaden our understanding of these tragic events and how to effectively prevent them.

First, researchers must abandon the starting assumption that acts of mass violence are driven primarily by diagnosable psychopathology in isolated “lone wolf” individuals, and must rather situate such destructive motivations within larger social structures and cultural scripts. Second, mental health professionals and scholars must carefully scrutinize any apparent correlation of violence with mental illness for evidence of racial bias in the official systems that define, measure, and record psychiatric diagnoses, as well as those that enforce laws and impose criminal justice sanctions. Third, to better understand the role of firearm access in the occurrence and lethality of mass shootings, research should be guided by an overarching framework that incorporates social, cultural, legal, and political, but also psychological, aspects of private gun ownership in the United States; what is needed is a sustained inquiry into how these dimensions might shape the contours of gun violence as a broader public health problem. Fourth, effective policies and interventions to reduce the incidence of mass shootings over time—and to prevent serious acts of violence more generally—will require an expanded body of well-funded interdisciplinary research that is informed and implemented through the sustained engagement of researchers with affected communities and other stakeholders in gun violence prevention. Emerging evidence that the coronavirus pandemic has produced a sharp increase both in civilian gun sales and in the social and psychological determinants of injurious behavior—especially in marginalized communities—adds special urgency to our agenda. 9

Acts of mass murder implicate the psychologies of perpetrators. A better understanding of the reasons behind their behaviors—a kind of “rationality within irrationality” 10 —remains important to the hope of preventing such crimes in the future. 11 Retrospective analyses suggest that a nontrivial minority of high-profile mass shooters demonstrated clinical symptoms, including paranoia, depression, and delusions, at some point in their lives. 12 – 14 Still, the assumption that mass shootings are driven solely or even primarily by diagnosable psychopathology stretches the limits of mental health expertise. It also sets up a false expectation that advancing neuroscience and better therapies to manage psychiatric symptoms will provide “the answer” to solving gun violence. There is no existing or forthcoming unified theory of impaired brain functioning or of cognitive, mood, or behavioral dysregulation that could adequately explain mass shootings or multiple-victim gun homicides.

Symptoms of mental illness by themselves rarely cause violent behavior and thus cannot reliably predict it. Certain psychiatric symptoms, such as paranoid delusions with hostile content, are highly nonspecific risk factors that may increase the relative probability of violence, especially in the presence of other catalyzing factors such as substance intoxication. 15 , 16 Yet the absolute probability of serious violent acts in psychiatric patients with these “high risk” symptoms remains low. In general, focusing on individual clinical factors alone leaves too much unexplained, as it tends to ignore the important social contexts surrounding mass shootings and multiple-victim homicides. 17 To assume that gun violence is primarily a problem confined to a perpetrator’s brain may impede inquiry into a ranges of factors that could be crucial to a full understanding of mass shootings—factors such as the perpetrator’s sex, race, socioeconomic status, relationships, attitudes, personal history, the place where a shooting occurs and the perpetrator’s (dis)connection to it, and the ways in which local gun cultures and unrestricted access to guns might create the conditions under which these events become more likely.

How can mental health research change the dominant narratives surrounding mass shootings and multiple-victim homicides, and thus broaden debates about the community effects of gun violence? Our selective literature review and research agenda present a strategy for moving beyond the “diagnose-the-mass-shooter” framework to a perspective that emphasizes the multi-determined nature of gun trauma. In so doing, we advocate for broadening the scope of concern and the potential contribution of mental health experts and researchers to include the larger gun-violence epidemic, recognizing its structural dimensions as within their purview, especially at the intersection with social science, public health, and other complementary disciplines.

AN AGENDA FOR MENTAL HEALTH RESEARCH INTO MASS SHOOTINGS AND MULTIPLE-VICTIM GUN HOMICIDES

1. move beyond simplistic mass shooter profiling and media-driven “diagnose-the-shooter” formulations to situate destructive motivations within larger social structures and cultural scripts.

Politicians and media commentators often quickly label mass shooters as “mentally ill” without defining the term and before any valid psychiatric history is known, simply on the basis of the aberrant nature of the crime itself: “What sane person could do such a thing?” Media-stylized accounts of the motivation of mass shooters tend to rely on misleading stereotypes of the inherent dangerousness of mental illness. When such accounts are widely adopted as master explanations for shooting rampages, the easily recognizable features of the narrative can obscure the role of many other potentially important contributing factors. These might include the perpetrator’s stressful economic circumstances and level of social disadvantage, maladaptive personality development in response to early-life trauma, the psychological sequelae of domestic violence exposure, aggrieved resentment and smoldering anger against individuals or groups perceived to be hostile and threatening, 18 and male gender and aberrant constructions of masculinity—all enhanced by the disinhibiting effects of substance intoxication and easy access to a semi-automatic firearm. These kinds of vectors and background conditions, often interacting with each other in complex ways, can be far more germane to comprehending a particular act of mass violence than a diagnosis of acute psychopathololgy. 19

Recent studies suggest that approximately 25% of mass murderers had exhibited a mental illness, but most of them had not appeared on the radar of either the mental health or law enforcement systems. 13 Similarly, a Federal Bureau of Investigation (FBI) study of 63 active-shooter incidents between 2000 and 2013 found that 25% of shooters were known to have been diagnosed with a mental illness of some kind, ranging from minor to more serious disorders. The study concluded that “formally diagnosed mental illness is not a very specific predictor of violence of any type, let alone targeted violence.” 12 These relatively weak associations highlight how mental illnesses in themselves rarely cause violent behavior and are not reliable predictors of multiple-victim gun crimes. 16 , 20

In some sense, each mass shooting incident is unique. Substance use comorbidity and a range of putative risk factors ranging from the shooter’s level of economic distress and housing insecurity to politically extremist attitudes and ideology, to social isolation have been cited as stressors in analyses of mass shootings. 21 No single variable emerged as a common feature of mass shooters. Still, the “diagnose-the-shooter” narrative persists and furthers a number of stigmatizing stereotypes, such as the notion that persons with mental illness resemble “ticking time bombs.” 11 , 22 Representations of people with mental illness as being irrationally and unpredictably violent can have real adverse consequences, ranging from community resistance to the placement of housing and treatment facilities for people with mental illness in particular neighborhoods, to the escalation of tense interactions between people with mental illness and law enforcement officers, often resulting in avoidable arrests and incarcerations and sometimes ending in fatal shootings by the police. 23 , 24

Defining an appropriate role for mental health practitioners in preventing mass shootings is inherently difficult. While recent studies have found that the majority of mass shooters did not show signs of acute psychosis or serious mood disorder, the estimated prevalence of psychiatric disorder is still higher among these perpetrators than in the general adult population. As we have already suggested, there is some evidence that certain combinations of clinical symptoms and affect patterns may temporarily increase risk of gun violence. Researchers have identified delusions, fixation, and perceived persecution as clinical symptoms that may precede violent behavior. 16 , 25 But does this implicate psychopathology in mass shooting, and therefore call for psychiatric surveillance and risk assessment to prevent at least some of these events?

Ironically in this context, disorders such as major depression and schizophrenia are often marked by psychomotor slowing, negative affect, intellectual disorganization, social isolation, and other symptom clusters that would seem to render a person less likely to plan and implement a complex gun crime. 18 , 26 It is perhaps not surprising, then, that some studies have found that persons diagnosed with these mental illnesses are less likely than non–mentally ill offenders to use firearms in violent crimes. 27 Along these lines, Swanson and colleagues 28 found that adults with serious mental illnesses in public behavioral health systems in Florida were at least no more likely than other adults in the general population to be arrested for a gun-related violent crime.

A study of individuals who were clinically fixated on harming members of Congress found that having a psychiatric diagnosis alone was not associated with aggression or actual violent behavior. More relevant predictors included the individual’s motives and means. 29 , 30 The MacArthur Violence Risk Assessment Study 31 identified a group of 100 repeatedly violent individuals in a sample of 1136 discharged psychiatric inpatients but found that psychosis immediately preceded only 12% of violent incidents. The researchers concluded that “psychosis sometimes foreshadows violence for a fraction of high-risk individuals, but violence prevention efforts should also target factors like anger and social deviance.” 32 In addition, the MacArthur study found that only 2.4% of the study participants engaged in any act of firearm-involved violence, defined to include brandishing or threatening someone with a gun, over the 12-month follow-up period. 31

A large U.S. study of schizophrenia patients in the community found that 5.4% of participants engaged in at least one act of injurious violence during an 18-month follow-up period, but baseline symptoms of psychosis or depression did not predict injurious violence. Rather, the significant predictors were severity of illicit drug use (hazard ratio = 2.93), recent violent victimization (hazard ratio = 3.52), childhood sexual abuse (hazard ratio = 1.85), and medication nonadherence (hazard ratio = 1.39). 33 These findings would suggest that the large majority of patients with schizophrenia do not engage in acts of serious violence, and even when they do, psychiatric symptoms alone do not provide a sufficient explanation for their violent behavior.

Still, “mental health” remains the focus of many existing regulations as well as proposed policies to prevent gun violence in the community. Despite evidence that there is no strong connection between gun crime and mental illness, 2 federal law since 1968 has prohibited firearm purchase or possession by anyone with a record of involuntary civil commitment to a psychiatric hospital or other mental health–related adjudication. 34 A few studies have suggested that this restriction prevents some violent crime—and gun crime, in particular—but its population-level impact is severely limited since very few patients are involuntarily committed. 35 , 36 The vast majority of violent gun crimes are perpetrated by people who would never be committable to a psychiatric hospital, and the important correlates of violent behavior tend to be the same in psychiatric and nonpsychiatric populations—for example, being young, male, or socially disadvantaged, exposure to trauma in early life, and using drugs and alcohol to excess. Future research into mass shootings and other acts of serious violence should move beyond the diagnostic template that looks for psychopathology to adequately explain the perpetrator’s behavior.

2. Scrutinize any Apparent Correlation of Violence with Mental Illness for Evidence of Racial Bias in the Official Systems That Define, Measure, and Record Psychiatric Diagnoses, as Well as Those That Enforce Laws and Impose Criminal Justice Sanctions

U.S. popular and political discourse frequently applies the mental illness descriptor to white male shooters, but analysis of whiteness itself, or discussions of whiteness as a race or ethnicity, are usually omitted from published studies about U.S. mass shootings. 37 – 39 By contrast, race and ethnicity often play a key role in accounts of mass shootings when the perpetrator is not white. For example, after the 2007 mass shooting at Virginia Tech University perpetrated by a college student of Korean-American heritage, media outlets reported that Asian-Americans experienced fear of retaliation and felt forced to issue an apology on behalf of their “group.” 40

A content analysis of news documents covering mass shootings from 2013 to 2015 found that white and Latinx male perpetrators were more likely to have their crimes attributed to mental illness than were shootings by black men. 41 White men were qualitatively described as more sympathetic characters than black and Latinx men, who were more often labeled as violent threats to public safety. 41 Despite the popular stereotype of mass shooters being white, statistically just over half (57%) of the perpetrators of FBI-defined mass shootings since the early 1980s have been white, and the majority of victims of mass shootings in recent years have been nonwhite individuals. 42 , 43 When a mass shooting occurs and the identified perpetrator is black, content analysis shows that politicians’ press briefings, media reports, and research articles rarely mention mental health and illness in descriptions of the perpetrator. Rather, such incidents are more likely to be described under rubrics such as “gang disputes,” “drive-by shootings,” or other forms of “urban” violence, often with little further elaboration on motives or effects. 44 , 45

These white/black dichotomies in the definition of mass shootings carry implications for resource allocation for studying these incidents and for potentially interrupting their causal pathways and mitigating their harmful consequences to individuals and communities. Defining urban violence as essentially out-of-range for our concern with mass shootings makes it much more difficult for researchers to discover the ways in which these shootings, too—as commonplace as they have become in certain urban neighborhoods—can have profound and lasting psychological and community effects. 46

Mass shootings in urban areas have received little attention from mental health researchers, and the relatively few studies on this topic mostly amount to superficial, group-based comparisons between urban and suburban perpetrators. For example, Knoll 47 describes aspects of social identity in summarizing how urban and suburban perpetrators seem to differ, citing an urban “honor culture” and strong, group-based “social hierarchies” as the context for urban mass violence, in contrast to the image an isolated loner who commits a mass shooting in a suburban public setting.

Meanwhile, a large body of research has focused on the link between violence and mental illness in general, much of it relying on data from the criminal justice system, forensic facilities, state psychiatric hospitals, or other publically funded systems in the community. Due to the historical nexus of racial discrimination and economic disadvantage—which had led indirectly to entrenched disparities in arrest and incarceration as well as to involvement with the public behavioral health system—individuals who are identified as violent (or at risk of violence) in official institutional settings tend to be disproportionately people of color. 48 – 50

These systems curate and disseminate the records of felony conviction and involuntary civil commitment that are used to determine that a person is ineligible to possess firearms under federal or state law. Specifically, official agencies report gun-disqualifying records to the FBI’s gun-purchase background check database, with the result that racial disparities in the reporting institutions’ practices and policies tend to be reproduced in the implementation of firearm restrictions that are applied to putatively risky categories of people. 51 As one example, a large study of gun restrictions in a population of adults with serious mental illnesses in Florida found that black individuals made up 15% of the surrounding population but 21% of the study group in the public behavioral health system, 31% of those disqualified from guns due to a mental health adjudication, and 36% of those disqualified due to a criminal record. 28 , 49

As a result of these entrenched selection effects, much of what we know regarding the intersection of violence and mental illness extends only as far as people with mental illnesses who are socially and economically marginalized or use public services. But this misleading picture is often used to justify further institutionalization or incarceration that disproportionately affects people of color, producing an insidious feedback loop between biased data and discriminatory practice. Studies that are able to account for a range of social correlates of violence in multivariable models tend to find that the statistical association between violence and race is much attenuated, as is the link between violence and mental illness as defined in the official records of state agencies. 31 , 52

In summary, racial bias can creep into available data and distort our understanding of mass shootings and other gun violence, limiting the scope of what should be a broader and more productive inquiry into the complex causes and effects of gun-related injury and death. What, for instance, are the psychologies that underlie shootings in areas of concentrated urban poverty, and what particular traumas emerge in their wake? 53 , 54 What are the traumatizing effects for young people who frequently hear gunshots or have seen shootings or dead bodies? 55 , 56 How can mental health expertise be effectively deployed to address these more quotidian, but no less problematic, aspects of gun violence in the United States?

Reckoning with the biases in its own framework can then aid mental health research to promote anti-racist work 57 —such as collaborating with community-based violence interrupters, 58 imagining and advocating for structural change, and addressing how gun victimization in black communities intersects with other unequal systems, including health care, education, and community safety. 46

3. Promote Awareness of the Social and Political Determinants of Firearm Violence

To better understand the role of firearm access in the occurrence and lethality of mass shootings and other forms of gun violence, research should be guided by an overarching framework that incorporates not only social, cultural, and political, but also psychological, aspects of private gun ownership in the United States. Mental health researchers should play a key role in a sustained collaborative inquiry into how these dimensions might shape gun violence as a broader public health problem. Following the lead set by public health scholarship, adopting such an approach would enable mental health researchers to contribute productively to building interdisciplinary evidence for gun laws and policies that are both effective and equitable, minimizing potentially adverse collateral consequences for at-risk individuals who are subject to restrictions. 59 Mental health professionals and scholars could have much to offer, for example, in the development of better guidelines for restoring firearm rights to persons with gun-disqualifying records in their remote past. 60

A study by Reeping and colleagues 61 found that states with more permissive gun laws and higher rates of gun ownership also tend to have higher rates of mass shootings. But do these patterns mean that gun laws are effective, or do they reflect the intersectionality of other social and economic differences among states? Research by Steadman, 31 Tuason, 62 and others suggests that serious acts of violence attributed to “mental illness” often are more robustly associated with socioeconomic factors that may also be indirectly linked to mental illness, including unemployment, insecure housing, histories of trauma, or lack of access to care. 63 Perhaps the broader determinants of population well-being, illness, injury, and death can independently affect all of the following: cultural attitudes toward gun ownership; responses to social conflict; policies and laws concerning gun access; the motivations of a mass shooter; and the probability of being able to carry out an act of mass violence. 64 Understanding such potential connections through interdisciplinary research that includes a trained mental health lens could help to both reduce gun violence and improve other dimensions of population well-being over time.

4. Use Community Engagement to Expand the Scope and Impact of Research to Prevent Mass Shootings and Other Gun Violence

Effective policies and interventions to reduce the incidence of mass shootings and other acts of serious violence will require an expanded body of well-funded interdisciplinary research that is informed and implemented through the sustained engagement of researchers with affected communities and other stakeholders. Within the mental health community, persons with lived experience as well as some family members and advocates have been loath to engage with gun violence prevention efforts in the past, due to the perception that these efforts play upon the public’s exaggerated fear of people with mental illnesses and thus exacerbate the stigma and scorn that mentally ill individuals feel from others. 65

In reality, people in the community who are recovering from serious mental illnesses often have more to fear from other people. Like other vulnerable populations, 54 , 66 , 67 persons diagnosed with mental illnesses are statistically more likely to be victims than perpetrators of violent crime. 18 , 68 , 69 They represent between 25% and 58% of those shot and killed by police officers each year, 70 , 71 and there is an apparent interaction between race and mental illness when citizens are shot by law enforcement officers. A recent study found that when police shot and killed people in the line of duty, their explanatory reports applied the label of “mental illness” more than twice as often to white individuals as to black individuals (32% vs. 15%). 72

These findings suggest the need for community-engaged research to explore how perceptions and potential biases surrounding mental illness and firearms intersect with those that involve race, gender, and class. 73 Such research could help to dismantle the stigmatizing assumption that mental illness causes violence, clearing the way for larger debates about community safety and resource allocation. This step could be important because studies have found that people who associate mental illness with danger are less likely to support allocating funds to community services and programs designed for individuals with mental illness. 74 – 77

Future research should determine what are the best practices for engaging communities in gun violence prevention, and should better promote existing efforts in that regard. For instance, following the Sandy Hook shooting, the Interdisciplinary Group on Preventing School and Community Violence recommended developing channels of communication between schools and surrounding communities. 78 Their report highlights “channels of efficient, user-friendly communication” and emphasizes the importance of ongoing dialogue between different community stakeholders such as students, parents, health care providers, security and safety officers, and school administrators. 78 Community-engaged mental health researchers who are focused on broadening the discussion and inquiry into why mass shootings occur may occupy a strategic position for informing and fostering such dialogue among stakeholders.

It is important to move beyond a preoccupation with determining the mental health status of mass shooters and, more generally, with the question whether “the mentally ill” are prone to gun violence. This preoccupation has served to limit the important role that mental health expertise could actually play in addressing broader questions involving the balance between the perceived benefits of gun ownership and the risk that guns may pose in the hands of some persons at certain times—all in the interest of promoting the well-being of individuals and society. The ability to acquire reliable data on the causes and consequences of gun violence was seriously hampered by a decades-long federal ban on funding for gun-related research at the Centers for Disease Control and Prevention. That ban, which prohibited any studies that could have been perceived as promoting gun control, had a chilling effect on all federal research funding aimed at preventing gun violence. But now that the ban has been at least nominally lifted and some new federal funds have been appropriated for such research at the CDC and National Institutes of Health, the time has come for mental health experts and researchers to join other scholars in complementary disciplines and seize the opportunity to build the next generation of research to prevent violence. They must develop broad conceptual frameworks and creative methodologies to study gun violence as the persistent and multifaceted public health crisis that it is, and to insist on a level of public investment commensurate with the human and societal cost that gun violence exacts.

The reviewed literature makes clear that a diagnosis of a mental illness alone is an negligible factor in any effort to explain, predict, and prevent mass shootings or other acts of serious gun violence. These tragic events have many individual and social determinants—from trauma history to substance dependence, from unemployment and insecure housing to the proliferation of guns in the community—that may interact with each other in complex ways. Public mass shootings are still rare events when considered at the population level, notwithstanding a fearful public’s perception of their frequency and salience; these will always be exceedingly difficult events to study, predict, and prevent. Filling in the gaps in knowledge about these events requires a better understanding of the cultures and contexts that surround guns in America, in addition to a focus on specific shootings. More broadly, preventing gun-related injuries and deaths is a collective, social responsibility. Psychiatry stands to be an agent of change in promoting interventions and solutions for improving the health of a community, rather than narrowly addressing the most sensationalized manifestations of gun violence.

This body of research becomes more salient as gun ownership emerges as an important theme in narratives surrounding America’s responses to the COVID-19 pandemic and the reckoning with racism in the aftermath of the killing of George Floyd. 79 Unprecedented surges in gun ownership, 80 weapons brandished in the lobbies of statehouses, 81 and armed presence at protests and counter-protests across the country 82 have marked the American pandemic moment. Mental health experts have also warned of a “perfect storm” for suicide risk that is especially concentrated in COVID-distressed communities, with a sharp increase in the socioeconomic and psychological determinants of self-injurious behavior coinciding with an influx of guns, the most lethal of suicide methods. And while these trends may heighten the risk of gun-related morbidity and mortality linked to mental illness, they also illuminate gaps, blind spots, and omissions in mental health expertise: we need to know more.

Just like mortality rates from the novel coronavirus, social vulnerabilities and inequities that contribute to gun trauma have been exposed and exacerbated by the shift in resources away from communities that were already at risk. Recent multiple-victim shootings in cities like Baltimore and Philadelphia were all the more lethal because first responders and emergency rooms were already deployed to capacity with COVID-19 treatment instead. 83 – 85

Future research will need to address ways in which U.S. gun trauma has morphed in relation to the changing structures surrounding human interactions. 86 For instance, the possibilities that previously public gun violence is shifting during the pandemic to private spaces or that it involves new or different victims are developments that heighten the urgency of recalibrating risk assessment and mounting interventions that can reach people where they reside.

Again, people who are already within the mental health system do not represent the highest-risk groups for many types of gun violence, such as intimate partner shootings and other stress-induced and alcohol-fueled tragedies that increasingly occur in private residences during the pandemic. 87 Calling the police is not always the most realistic or desired first step in these delicate situations; mental health experts might, instead, need to develop new networks through partnerships with organizations, technology platforms, and services that reach individuals in threatening circumstances. Here, for instance, mental health knowledge tailored to these situations could be adapted and disseminated by social media companies, first responders, employment boards, or other delivery services. 18

By reframing and broadening their approach to mass-casualty shootings, mental health professionals and researchers could move mental health expertise to the fore in promoting firearm safety in schools, workplaces, and public gatherings, and among and between differing communities in post-pandemic America. 88 Moving beyond diagnostic frameworks and the futile quest to “foresee” mass shootings will allow mental health research to more fully address how mass shootings and multiple-victim homicides occur within broader systems and frameworks. Doing so could broaden our understanding of gun violence and point the way to fair and effective policy solutions that could save many lives, while respecting both the rights of gun owners and the dignity of persons affected by mental illness. 89

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Acknowledgments

This article and the research behind it would not have been possible without the exceptional support of Jeffrey Swanson, PhD. His enthusiasm and exacting attention to detail have been an inspiration, and our findings reflect his ongoing encouragement, generosity, and breadth of knowledge.

Original manuscript received 18 February 2020; revised manuscripts received 25 June and 6 October 2020, accepted for publication subject to revision 27 October 2020; revised manuscript received 2 November 2020.

Stress of mass shootings causing cascade of collective traumas

The regularity of mass shootings is razing Americans’ mental health—heightening stress and dulling compassion in ways that demand broader concern, engagement, and change

Vol. 53 No. 6 Print version: page 20

• Gun Violence and Crime

As mass shootings continue to erupt in schools, grocery stores, restaurants, and other public places and establishments we visit every week, Americans are living in fear. For children and teens, whose mental health is already in crisis , the ongoing backdrop of violence is steadily eroding the sense of well-being, safety, and efficacy known to be essential for healthy development. As of Oct. 26, there have been 566 mass shootings reported and verified in the United States in 2023, according to the Gun Violence Archive . The incidence of mass shootings in the United States is growing and is correlated with increases in gun sales ( Newsome, K., et al., Journal of Surgical Research , Vol. 280, 2022 ).

On top of recent surges in depression, anxiety, and suicides, a majority of teens now say they worry about a shooting happening at their school ( Pew Research Center , 2018). Those concerns have been linked with elevated anxiety levels and fear among students (O’Brien, C., & Taku, K., Personality and Individual Differences , Vol. 186, 2022 ). Meanwhile, clinical psychologists, including Erika Felix, PhD, of the University of California, Santa Barbara, say the young people they treat are on high alert, constantly planning their escape route if violence breaks out in public.

“These tragedies are happening far too often, and the result is that many young people are feeling this constant back-of-the-mind stress,” Felix said.

That stress is, of course, embedded within the context of the pandemic, the conflicts in the Middle East and Ukraine, economic challenges, political polarization, climate-related disasters, and other factors, which combine to create what psychologist Roxane Cohen Silver, PhD, of the University of California, Irvine, calls a “cascade of collective traumas” that the nation is facing together.

“We’re not starting at a place where everybody is healthy and thriving,” said Rinad Beidas, PhD, a professor of psychiatry, medical ethics and health policy, and medicine at the University of Pennsylvania’s Perelman School of Medicine. “Our reserves are depleted as a nation and our young people are suffering.”

Fear of mass shootings has left a large majority of Americans feeling stressed, including a third of adults who say they now avoid certain places and events as a result ( Stress in America: Fear of mass shootings , APA, 2019). Experts say the frequency of mass shootings, amplified by our near-constant access to media coverage of such events, amounts to an accumulation of exposure that is harming everyone’s mental health.

[ Related: APA resources for coping with mass shootings ]

“The more catastrophic events we’re exposed to as a nation, the more impacted we’re going to be on a psychological level,” said Jonathan S. Comer, PhD, a professor of psychology and psychiatry at Florida International University.

While some people report panic and distress, others feel numb. Psychological reactions to a crisis vary from one person to the next, based on factors such as age, trauma history, and proximity to an incident. But research has started to reveal who is most likely to be affected, what the long-term mental health problems will be, and what role media exposure plays. Psychology offers guidance about how to channel concern into action amid these atrocities.

“We’re at a really important inflection point as a country where we all understand that what’s currently happening with regard to mass shootings cannot continue,” said Beidas, who also directs the Penn Medicine Nudge Unit and Penn Implementation Science Center. “I come to this with a lot of hope that we’re all recognizing that it’s time to do things differently.”

A cycle of distress

Mass shootings account for about 1% of annual firearm deaths in the United States, but they occupy an outsize space in the public consciousness.

“These events are still relatively rare, but it doesn’t feel that way,” said school psychologist Franci Crepeau-Hobson, PhD, an associate professor and director of clinical training at the University of Colorado Denver’s School of Education and Human Development. “I think that everybody’s sense of security has been threatened.”

For survivors and witnesses of mass shootings, suffering tends to be particularly severe. Studies have documented increases in posttraumatic stress disorder (PTSD), major depression, anxiety disorders, substance use disorder, and other conditions among people who have survived a mass shooting.

“A common theme is that more exposure tends to be associated with more severe symptoms,” said clinical psychologist Sarah Lowe, PhD, an assistant professor of social and behavioral sciences at Yale School of Public Health, who led a 2015 literature review on the mental health consequences of mass shootings ( Trauma, Violence, and Abuse , Vol. 18, No. 1, 2015 ).

But the research is still very limited. In Lowe’s review, PTSD prevalence ranged from 3% to 91%, depending on the study, and methodological questions remain, such as what even constitutes a mass shooting.

Though relatively few people will witness or survive mass shootings, many more will experience them through news reports and social media.

“There’s a great deal of evidence that individuals who are far away from mass shootings can face anxiety and impairments, and this is often correlated with the amount of media exposure they have,” Comer said.

Such findings are highly concerning given how intertwined people’s lives are with media, researchers say. Silver and her colleagues have studied that link for more than 20 years, showing how high levels of exposure to media coverage of 9/11 and the Boston Marathon bombings predicted symptoms of acute stress and posttraumatic stress ( Psychological Science , Vol. 24, No. 9, 2013 ; PNAS , Vol. 111, No. 1, 2014 ).

Over time, media exposure to mass violence can even fuel a cycle of distress, where persistent worry about future violence predicts more media consumption and more stress, the researchers found (Thompson, R. R., et al., Science Advances , Vol. 5, No. 4, 2019 ). That constant worry, known as “perseverative cognition,” has been linked to declines in physical health, including cardiovascular problems (Ottaviani, C., et al., Psychological Bulletin , Vol. 142, No. 3, 2016 ; JAMA Psychiatry , Vol. 65, No. 1, 2008 ).

In addition to the risks of media exposure, people with a history of trauma are more likely to experience posttraumatic stress (PTS) symptoms following a new exposure, such as a terrorist attack or mass shooting (Garfin, D. R., et al., Psychological Science , Vol. 26, No. 6, 2015 ). Physical proximity to an incident also carries a higher risk of mental health problems. One study of 44 school shootings found that antidepressant use increased more than 20% among young people who lived within 5 miles of a shooting, versus those who lived 10 to 15 miles away (Rossin-Slater, M., et al., PNAS , Vol. 117, No. 38, 2020 ).

Psychological proximity—the degree to which we relate to another person or an event—also increases the risk for PTS symptoms (Thoresen, S., et al., European Journal of Psychotraumatology , Vol. 3, No. 1, 2012 ).

“Oftentimes, the more one identifies with the victims, the more difficulty they have in the aftermath of an event like this,” Comer said.

While some people worry regularly about mass shootings, many are fatigued by the seemingly endless cycle of violence that moves rapidly through the media and public discourse.

“There’s not one single way people are experiencing these tragedies, and there’s no one-size-fits-all response,” Silver said. “One person might be very impacted by an event, and another may not be concerned about it at all.”

Research by cognitive psychologists helps explains how we perceive mass violence and why it can leave some people feeling numb. Paul Slovic, PhD, a professor of psychology at the University of Oregon, and his colleagues have shown that in many cases, the more people who die in an incident of mass violence, the less we care. They call this phenomenon the “ deadly arithmetic of compassion .”

Their research shows that people’s intuitive feelings of concern for victims of violence don’t respond well to statistics and don’t scale up. In other words, the horror people felt when 19 children and two adults were shot and killed at Robb Elementary School in Uvalde, Texas, isn’t 21 times greater than what people feel when one child is murdered. Slovic and other psychologists call this dampening of the emotional response “psychic numbing.”

At the same time, people often have a false sense of inefficacy in the face of very large problems, which can lead to inaction and disengagement. In one study, participants who saw statistics about the magnitude of the hunger crisis in Africa donated about half as much money as those who saw a photo of a single child in need ( PLoS ONE , Vol. 9, No. 6, 2014 ).

“If we believe there’s a problem that we can’t do anything about, it makes sense that we don’t attend to it, because it’s very distressing to dwell on things you can’t fix,” Slovic said.

Finally, research on what’s known as the “prominence effect” shows how people often struggle to make decisions when they require weighing complex tradeoffs ( University of Illinois Law Review Slip Opinions , 2015). In the case of gun legislation, this helps explain why the complex calculus of lives saved versus freedoms sacrificed has largely resulted in inaction at the policy level.

And on top of this deadly arithmetic, our attention is a scarce resource. Time passes, memories fade, and we’re inclined to shift our attention elsewhere if we don’t see progress. National surveys have shown that support for gun legislation spikes in the immediate aftermath of a mass shooting but fades within a few weeks (Jose, R., et al., Psychology of Violence , Vol. 11, No. 4, 2021 ; Filindra, A., et al., Social Science Quarterly , Vol. 101, No. 5, 2020 ).

“Our mind deceives us into underreacting to the most important problems in the world, including mass violence,” Slovic said. “But when one of these events occurs, we do have a window of opportunity when people are awake, emotionally engaged, and motivated for action.”

Youth on high alert

The stress of mass shootings may weigh particularly heavily on children and teens, whose mental health is already in turmoil. In 2021, three leading pediatric organizations declared a national emergency , while the U.S. Surgeon General issued a special advisory on youth mental health , citing a 57% increase in suicides between 2007 and 2018 (Curtin, S. C., National Vital Statistics Reports , Vol. 69, No. 11, 2020 ).

Research shows that at least some of that distress can be attributed to mass violence. One study of more than 2,000 teens found that greater concern about school shootings and violence predicted increases in anxiety and panic six months later (Riehm, K. E., et al., JAMA Network Open , Vol. 4, No. 11, 2021 ).

“When I talk to kids about this, I am shocked by how inured and accepting they are,” said Don Grant, PhD, the executive director of outpatient services for Newport Academy in Santa Monica, California, and is president of APA’s Division 46 (Society for Media Psychology and Technology). “They don’t know a world where there’s not an active shooter drill at school.”

In the educational context, that constant vigilance can be particularly problematic, and research on threat perception suggests that prolonged heightened anxiety may interfere with learning, said Crepeau-Hobson. Students who are constantly worried about a toxic stressor, such as gun violence, devote more mental resources to emotions and fewer to executive functions, including learning, memory, and sustaining attention (Dettmer, A. M., & Hughes, T. L., Education Week , 2022).

“When threat perceptions are escalated and stress responses are activated, we can’t access the higher parts of our brain,” Crepeau-Hobson said.

Data suggest those effects could be far-reaching. A 2020 report from the National Bureau of Economic Research found that school shootings increased absenteeism, reduced high school and college graduation rates, and decreased retention of teachers. Those effects persisted into the mid-20s of young adults who attended schools where a shooting occurred; they had lower employment rates and earnings than their peers (Cabral, M., et al., NBER Working Paper 28311 , 2022).

“It’s not just that individual young people experience these really deleterious effects, but there is also a societal effect,” Beidas said.

Because mass shootings impact children and teens at the individual, institutional, and societal levels, experts say a tiered approach is needed to minimize harm.

In the family context, it’s important to initiate conversations with children and teens after an incident, even if they aren’t part of the affected community, said Comer.

“When kids hear about these events from their parents, they tend to do better than when they hear about it from their friends or the media first,” he said.

If a child or teen becomes hypervigilant or starts to avoid certain places or activities, that may indicate a need for professional support, said Grant.

Educators and policymakers also need empirical data on what makes schools safe—both physically and psychologically, said Crepeau-Hobson, a member of the APA’s Division 16 (School Psychology) executive committee.

“A number of schools are wasting their resources on strategies that aren’t particularly helpful, without thinking about their psychological impact on children who are coming to school to learn,” she said.

School districts across the nation are spending billions of dollars to enhance security, installing emergency alert systems and hiring additional personnel. But many of the new approaches lack evidence and could even cause harm. For example, a law enforcement presence may make some students feel safer but may undermine a sense of safety in others, such as students of color. Early studies of active shooter drills—which are now nearly ubiquitous—suggest they may increase anxiety, stress, and depression symptoms in children and adolescents (“ The Impact of Active Shooter Drills in Schools ,” Everytown Research and Policy , 2020).

Communities also need to be prepared to support children in the immediate aftermath of a mass shooting. Last year, Comer launched the Network for Enhancing Wellness and Disaster-Affected Youth ( new day ), which delivers large-scale professional training on disaster mental health across the country. new day teaches Psychological First Aid and other skills to teachers, coaches, nurses, and others who work with children and teens.

Sustaining engagement

More research is also needed on how mental health services can best support survivors, families, and affected communities in the aftermath of a mass shooting, experts say. Richer firearm-injury and mortality datasets can also help researchers better understand the conditions surrounding these crises.

But many feel change is urgently needed, and that partnering with the firearm community—to promote more secure storage of firearms, for example—is one way to start reducing firearm injuries and deaths right away, Beidas said.

More than 7 million Americans bought firearms for the first time between January 2019 and April 2021, mostly for self-protection (Miller, M., et al., Annals of Internal Medicine , Vol. 175, No. 2, 2022 ). That suggests many people need education on secure storage (see “ Talking to patients about firearm safety,” April 2022 Monitor ), and that the recommended method of storing a gun unloaded and locked, with ammunition locked separately, might not be acceptable to all firearm owners.

“We need to establish a shared mission with the firearm community,” Beidas said, “and keep in mind that a harm reduction approach is the most effective way to change behavior.”

At the policy level, a majority of Americans support stricter gun laws, but progress in that domain may be incremental (Jose, R., et al., Psychology of Violence , Vol. 11, No. 4, 2021 ). Slovic said it’s important to stay engaged and not to let a false sense of inefficacy prevent us from taking steps in the right direction.

“Just because we can’t fix a problem in its entirety doesn’t mean that we shouldn’t do what we can do to make a difference,” he said. “We cannot afford to let our minds deceive us into underreacting.”

Further reading

Empowering communities to prevent mass shootings Stringer, H., Monitor on Psychology , January 2022

When the shooting stops: The impact of gun violence on survivors in America Everytown Research and Policy , 2022

Coping with cascading collective traumas in the United States Silver, R. C., et al., Nature Human Behavior , 2020

Prevention of firearm injuries among children and adolescents Cunningham, R. M., et al., JAMA Pediatrics , 2019

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How Do Mass Shootings Affect Community Wellbeing?

Over the past four decades, more than 2,300 people have been the victims of mass shootings involving a firearm in the United States. Research shows that mass shootings have significant detrimental effects on the direct victims and their families. However, relatively little is known about the extent to which the impacts of these tragedies are transmitted into communities where they occur, and how they influence people beyond those directly affected. This study uses nationally representative data from the Gallup-Healthways survey to assess the spillover effects of mass shootings on community wellbeing and emotional health outcomes that capture community satisfaction, sense of safety, and levels of stress and worry. We leverage differences in the timing of mass shooting events across counties between 2008 and 2017. We find that mass shootings reduce both community wellbeing and emotional health. According to our results, a mass shooting is associated with a 27 percentage point decline in the likelihood of having excellent community wellbeing and a 13 percentage point decline in the likelihood of having excellent emotional health four weeks following the incident. The effects are stronger and longer lasting among individuals exposed to deadlier mass shootings. Furthermore, the reductions in wellbeing are greater for parents with children below age 18. Our findings suggest that mass shootings have significant societal costs and create negative spillover effects that extend beyond those immediately exposed.

The authors thank Analisa Packham and seminar participants at the Provost’s Distinguished Lecture Series at American University for comments and suggestions. Kathryn Johnson, Colleen Mattingly, and Alexandra Rakus provided excellent research assistance. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.

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