Madmen with guns: The relationship between mental health and mass shootings in the United States

Madmen with guns: The relationship between mental health and mass shootings in the United States

Increasing firearm responsibility and safety and reducing mental health stigma to allow seeking treatment may benefit violence prevention efforts and minimize mass shootings. This is the bottom line of a recently published article in Psychology, Public Policy, and Law. Below is a summary of the research and findings as well as a translation of this research into practice.

Featured Article | Psychology, Public Policy, and Law | 2016, Vol. 25, No. 3, 212–223

Mass shootings in the United States: Understanding the importance of mental health and firearm considerations


Logan A. Yelderman , Prairie View A&M University
Justin J. Joseph, Prairie View A&M University
Matthew P. West, University of Nevada, Las Vegas
Erycha Butler, Prairie View A&M University


The purpose of this study was to examine whether mass shooters’ media-reported mental health history and firearm access related to mass shooting severity. The current analysis included a total of 102 mass shooters in the United States between 1982 and 2018 described in media reports. Negative binomial regression analysis was used to assess if a shooter’s media-reported mental health history and firearm access were related to mass shooting severity while controlling for age, race, location, weapon attainment legality, and assault rifle use. Results suggest that reported mental health histories, number of weapons brought to the scene of the crime, weapon attainment legality, the use of an assault-style weapon, and location were significantly related to mass shooting severity. Understanding the relationships between gun access, mental health, and mass shooting severity might provide a better foundation for policy development aimed at minimizing mass shootings. Unaddressed mental health issues might increase violence; therefore, reducing mental health stigma might enable more individuals to seek formal evaluations, which could assist violence prevention efforts. Similarly, increased firearm responsibility and safety, whether at the social or legal level, might reduce violence and prevent casualties of mass shootings.


mass shooting, violence, gun control, mental illness, policy

Summary of the Research

“The three deadliest mass shootings in the United States occurred in the last decade. On April 16, 2007, Virginia Tech experienced the third most fatal school shooting to date, sparking debates of campus safety and gun control nationwide. Seung-Hui Cho shot himself after he killed 32 students and faculty, injured 17, and caused psychological trauma for many others. After this event, information surfaced that Cho had a history of mental health issues since childhood, directly linking mental illness to this particular mass shooting.” (p. 212)

“The second deadliest recorded mass shooting in the United States occurred 9 years later on July 12, 2016, when Omar Mateen shot and killed 49 patrons and injured 53 patrons at the Pulse nightclub in Orlando, Florida. Again, the news linked the shooting to mental illness, particularly after Mateen’s ex-wife reported he had a history of mental health issues.” (p. 212)

“Most recently, Stephen Paddock killed 58 people and injured over 500 others at a country music festival in Las Vegas, Nevada in the deadliest mass shooting in the United States to date. Similar to the other cases, reporters, law enforcement, and public media representatives scrambled to name a motive, suggested a probable association with mental illness, and used mental health terms (such as psychopath) to describe the shooter. Consistent across all of these cases is the attempt to attribute the shooter’s behavior to mental illness, as well as subsequent discussions of gun control legislation.” (p. 212)

“Past research suggests mass shootings increase stigma associated with mental health, reinforcing the negative stereotype that people with mental illness are more dangerous and prone to violence than people without a mental illness. However, previous literature has not examined if mass shooters with prior mental health histories are more dangerous than mass shooters without mental health histories; thus, there is no empirical evidence to determine the role of mental illness in contributing to harm. Also, mass shooting events can engender the adoption of public policies associated with gun control, which are based on the presupposition that mass shooters are to blame for high firearm homicide rates.” (pp. 212–213)

“Such assumptions might lead to hastily adopting policies and using financial resources to address issues, potentially without regard to social costs, while failing to resolve problems of high homicide crime rates. Public policies discussed in the context of mass shootings espouse themes of safety from individuals with mental illness and restricted access to firearms as if mental illness and access to firearms have been demonstrated to equate to a person becoming a mass shooter. In this study, we examine how mass shooters’ media-reported mental health histories and weapon access relate to mass shooting severity (i.e., the total number of victims killed or injured in a single mass shooting event).” (p. 213)

“In the United States, mass shootings have become common in public discourse and media coverage. Though numerous mass shooters do not suffer from any mental disorders and their attacks are often thoroughly planned, the belief that mass shootings are random and perpetrated by mentally ill individuals is pervasive in the public. Media reports identifying violent mass shooters as mentally ill might cause widespread moral panic and incite public fear and uncertainty toward individuals with mental illness. Such reports might also lead to public support for gun and crime control, potentially through mental health interventions supported by legislators, political figures, or interest groups.” (p. 213)

“Integrating the two common themes of mental illness and gun control that arise after mass shootings, it is possible that legislation concerning firearm ownership and mental illness is a potential consequence of moral panic. However, moral panic does not necessarily mean that the public response is misguided. Calls for stricter gun legislation after mass shootings might even put pressure on gun manufacturers to enact gun safety reforms. Public panic, though potentially exaggerated, might be a response to a real threat, but such claims need empirical support.” (p. 213)

“Firearm legislation varies widely across the United States, including (but not limited to) policies on firearm purchasing and selling, firearm ownership, firearm storage, and firearm carrying. […] Firearm purchase legislation has included several attempts to reduce violence by placing requirements or restrictions on the purchasing process. Lower firearm homicide rates were reported in jurisdictions with stricter dealer regulations and stricter purchasing regulations, such as permit to purchase laws. Similar patterns in suicide were reported in jurisdictions with stricter purchasing and ownership regulations. However, not all restrictive legislation prevents individuals who do not meet the purchasing criteria from purchasing firearms. Nonetheless, gun control policies beyond ownership and purchasing have been passed to attempt to regulate gun safety among gun owners.” (p. 213)

“Although generally applied firearm legislation likely impacts mass shootings, targeted legislation, specifically targeting mass shootings, might aid in reducing mass shooting violence along with other firearm-related violence. To develop such policies, novel and innovative research is needed to inform courts and policymakers as to who might be a risk, which regulations reduce gun violence, which policies are effective, and where to focus policy efforts.” (pp. 213–214)

“Mental illness is quite prevalent throughout the United States. […] Among those diagnosed with severe mental illness, approximately 3–5% engage in violent behavior. Despite such low rates, the public belief that mental illness is associated with violence is pervasive. This perception may be, in part, influenced by research associating mental illness with intimate partner violence, violent victimization, and general violent perpetration. There is substantial literature suggesting severe mental illness is not a direct cause of violence, but this research has been largely neglected in the development and support for firearm legislation.” (p. 214)

“In the United States, firearm legislation concerning people with mental illness appears to be fueled by moral panic and selective references to evidence linking mental illness and violence. Numerous gun laws include restrictions for individuals with mental health histories. The National Instant Criminal Background Check System Improvement Amendment Act (NIAA) was passed following the mass shooting at Virginia Tech. It provided incentives for states to report individuals denied firearms because of noncriminal reasons (e.g., mental illness). Since the inception of NIAA legislation, increased reporting has occurred nationally; denial of gun ownership based on mental illness has become the second largest category.” (p. 214)

“These policies imply mental illness as an aggravating factor in firearm access, ownership, and violence. Passage of these types of laws likely perpetuates negative stereotypes associated with mental illness, leads to overidentification of at-risk individuals (disqualification from firearm purchases), and discourages individuals from seeking mental health assistance. However, the link between mental illness and violence does not necessarily directly affect people’s behaviors regarding firearm access, though it might affect their attitudes and emotions surrounding the issue.” (p. 214)

“The current study examined the relationships between firearm access, mass shooters’ mental health histories, and the total number of mass shooting victims using a data set of mass shooting events between 1982 and 2018 compiled from media reports. The present research addressed the assumptions that mental illness and firearm access are related to violence among mass shooters. In addition, the present research examined the belief that increased access to firearms by mass shooters would be associated with more severe mass shootings when the shooters had mental health histories than when they did not. Pertinent to this study, as it relates to the general discussion of mass shooters, is that this study did not attempt to predict who will become a mass shooter. Instead, the current study sought to provide evidence regarding the relationship between mental health and weapon access of known mass shooters as it related to mass shooting victim totals.” (p. 214)

“The first research question for the current study was, “Do mass shooters who have access to more firearms at the time of the crime shoot more victims?” […] The second research question was, “Do mass shooters with formally diagnosed mental illnesses or recognized mental health issues victimize more people than those without mental illnesses or mental health histories?” […] The second research question was, “Do mass shooters with formally diagnosed mental illnesses or recognized mental health issues victimize more people than those without mental illnesses or mental health histories?” […] The fourth question was, “Do mass shooters who use assault weapons victimize more people than mass shooters without assault weapons?” […] The fifth and final research question was, “Do mass shooters who obtain weapons illegally victimize more people than those who obtain them legally?”” (pp. 214–215)

“The current research used data collected by Mother Jones on mass shootings between August 1982 and June 2018. […] Mother Jones’s dataset was compiled of details and information for each mass shooting case made available through news reports. […] The Mother Jones data were also chosen because they included shootings that occurred in places violence typically does not occur but appears random, senseless, and openly public.” (p. 215)

“The key finding from this study is that reported mental health history was associated with increased violence among mass shooters when a disorder was identified but no specific formal diagnosis was reported. This finding was a reflection of media portrayals of mass shootings and was not based on formal independent assessments. Because formal assessments of mass shooters were often difficult to obtain (e.g., not released by mental health professionals) or impossible to obtain (e.g., assessments could not be obtained because of the shooter’s suicide after the shooting), journalistic representations of these facts were relied upon. In addition, shootings considered more violent as a result of more total victims were associated with shooters who used legally purchased weapons, brought more weapons to the shooting, and used an “assault weapon.””(p. 217)

Translating Research into Practice

“The results have numerous implications for policy and legislation. A possible conclusion based on these results is that decreasing access to firearms would reduce the number of mass shooting victims overall. More specifically, targeting assault weapons, through an assault weapons ban or similar policy, might appear to be plausible policy because mass shootings involving assault weapons made up only 23.5% of the total mass shootings yet accounted for 52.3% of the total mass shooting victims in this particular study. “ (p. 218)

“One might be tempted to conclude that this means the worst shootings occur with assault weapons; however, upon inspection of the worst cases recorded, only four of the top eight worst cases (cases with the most victims) included an assault weapon. To assume that banning assault weapons will prevent the worst mass shootings is slightly misleading, according to the current data. However, the increased violence among mass shooters who use an assault weapon is undeniable, which is why an assault weapons ban might appear to be a plausible route of action though it might face difficulties in the United States. […] Rather than banning assault weapons, an assault weapon ownership cap or purchase limitation policy might be more effective. Outright bans would likely face stark opposition and not garner enough support, but caps or limitations might be a more widely acceptable way to curb mass shooting violence.” (p. 218)

“If some sort of cap or limitation policy was enacted, it is critical to understand that policy implementation, of course, is arguably equally important as the policy itself. Providing clear and direct guidelines for implementing the policy is critical to address shortcomings of earlier policies that result in discrepant outcomes. Along these lines, one benefit of a firearm cap or limitation policy is that it could still serve a crime control objective even if the policy was difficult to widely and consistently enforce.” (p. 219)

“[Another] conclusion one might make from the current data is the need to implement stricter mental health policies associated with firearm purchases, ownership, and carrying in public. Mass shooters with reported mental health histories but no reports of formal diagnoses were more violent, according to the current study. In many of these cases, acquaintances and those close to the shooters were unsurprised by the shooters’ actions or recalled red flags in hindsight. Without a formal diagnosis, it is unclear whether these shooters ever had contact with a psychologist or psychiatrist. Without formal contact, mental health screens and background checks would not identify these individuals as high risk or prevent them from purchasing or acquiring firearms. Stricter mental health screens and purchase policies might be inadequate in addressing mass shooting violence, similar to assault weapon bans, though it is possible they could be effective in reducing overall gun violence.” (p. 219)

“Although this research suggests that mental health and firearm responsibility are important considerations for state and federal policy development and future research, they are also important for community discussions, violence awareness campaigns, and local public health interventions. Rather than interpreting mass shootings as a mental health or law enforcement failure, it might be better if mass shootings were understood as a symptom of a societal issue regarding mental health attitudes, gun ownership, and perceptions of violence. Increased social cohesion, social accountability, mental health stigma abolition, and empathy taught through local programs and interventions will be more likely to reduce mass shooting violence compared to federal legislation.” (p. 219)

“The current study provides evidence that completely discounting mental health as a risk factor in mass shootings is ill-considered and might mislead future discussions on mass shooting prevention and firearm violence reduction. […] However, the results of this study also emphasize the importance of understanding the context in which mental health relates to mass shooting violence. Using a blanket approach, suggesting that all individuals with mental illness are more violent is indeed incorrect. According to the current data, mental illness in general is not a risk factor in mass shooting violence, but specifically mental illness that is acknowledged or reported but not formally diagnosed.” (p. 219)

“Although the specific role of a formal diagnosis is unclear, there are two possible explanations for an associated reduction in mass shooting violence. First, it is possible that mass shooters who have had formal diagnoses have also received formal treatment to some extent, whether in the form of medication or therapy. This treatment might then have translated into more control and a lower likelihood to devolve during a mass shooting event. However, without specific information about toxicology at the time of the shooting and treatment history, this explanation is purely speculative. Second, and perhaps more likely, a formal diagnosis might be representative of a formal acknowledgment of a person’s mental illness and overall mental health. Any formal acknowledgment of one’s diagnosis might be accompanied by enhanced access to care and treatment, increased awareness among close relatives and acquaintances of a person’s potential mental illness episodes, an increased sense of accountability and responsibility among family and friends, and increased social support.” (pp. 219–220)

Other Interesting Tidbits for Researchers and Clinicians

“Although the current research provides unique insight into the mental illness and access to firearms debate regarding mass shootings, there are several notable limitations. First, this study uses secondary data compiled by the Mother Jones news organization and does not include all mass shootings. Specifically, it does not include mass shootings associated with other crimes or gang activity, and it does not include family slayings with numerous victims.” (p. 220)

“Second, mental health information was only assessed when made available. It is possible that some cases might have involved shooters with mental health histories that were never reported to the public. […] Third, some cases included multiple shooters. In these cases, shooters were split into two separate independent cases; however, it is impossible to know who was responsible for which victims.” (p. 220)

“Fourth, the mental health assessments were based on media accounts of mental health assessments and not formal assessments by clinical professionals under the direction of the researchers. Also, though rigorous methods were used to evaluate these reports, the specific mental health assessments were unable to be evaluated directly. […] Lastly, one of the reports used in the analysis of mental health histories was family reported mental health. Family reported mental health likely varies more compared to reports by psychologists or psychiatrists. Thus, a reliance on reports only generated and indicated by professionals might yield different results.” (p. 220)

“Future research should examine the extent to which mental illness and access to firearms relate to other mass shootings that did not fit the criteria utilized in the current study and other types of firearm violence. Environmental and social variables should also be identified and included in predictive models to explore the extent to which social isolation and exclusion relate to increased violence among mass shooters. Investigating why formal diagnosis plays a role in mass shooting violence seems important to pursue based on the current research. Though difficult, it would be interesting to measure more nuanced individual differences (e.g., personality characteristics) among mass shooters and how they relate to mass shooting violence. Lastly, future research should assess mass shooting facts in official and formal reports rather than media portrayals as this might improve validity and replicate findings in this study.” (p. 220)

Join the Discussion

As always, please join the discussion below if you have thoughts or comments to add!

Authored by Kseniya Katsman

Kseniya Katsman is a Master’s student in Forensic Psychology program at John Jay College of Criminal Justice. Her interests include forensic application of dialectical behavior therapy, cultural competence in forensic assessment, and risk assessment, specifically suicide risk. She plans to continue her education and pursue a doctoral degree in clinical psychology.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.