Mental Illness and Gun Violence in US, Australia, UK

Author: Florida Atlantic University
Published: 11 Dec 2023 - Updated: 15 Jul 2026
Publication Details: Peer-Reviewed | Case Study

Table of Contents:
Synopsis - Definition - Overview - FAQs - Insights, Updates - Related Content

Synopsis

This report, a peer-reviewed case study published in The American Journal of Medicine, compares rates of mental illness and gun violence across the United States, Australia, and the United Kingdom and reaches a pointed conclusion: although self-reported mental illness is roughly similar in all three countries, U.S. death rates from gun violence run more than ten times higher than Australia's and more than forty times higher than the U.K.'s. Led by researchers at Florida Atlantic University's Schmidt College of Medicine, the analysis points to the sheer prevalence of firearms and ease of access, rather than mental illness, as the plausible driver of that gap. The findings matter for policymakers, mental health professionals, and advocates for people with disabilities and seniors, because they push back on a common assumption and reframe where prevention efforts might most usefully be directed for populations that are often more vulnerable to both violence and self-harm.*

At a Glance

• 1 - In 2021, 47,286 Americans died from gun violence, of which 46 percent were homicides and 54 percent were firearm suicides.
• 2 - The U.S. has about 393 million guns among roughly 335 million people, or 1.2 guns per person, compared with about 0.13 guns per person in Australia.
• 3 - Gun death rates vary sharply by state, from a low of 3.4 per 100,000 in Massachusetts to 33.9 per 100,000 in Mississippi, a spread more than six times wider than differences in mental illness.

Topic Definition

Gun Violence

Gun violence is any violence carried out with a firearm, and it spans a wider range of events than many people assume. It can be criminal, as in homicide, assault with a deadly weapon, and suicide or attempted suicide depending on the jurisdiction, or non-criminal, as in accidental and unintentional injuries and deaths. Researchers studying the subject consistently find a correlation between how widely guns are owned in a population and the rates of both gun homicide and gun suicide within it. The scale differs dramatically between nations: the United States records a gun homicide rate many times that of comparable high-income countries and a total firearm death rate far above wealthy nations with strict gun control laws such as Japan, the U.K., and South Korea, which is why gun access sits at the center of most public health discussions of the problem.

Overview

"Mental Illness and Gun Violence in the United States, Australia and United Kingdom: Clinical and Public Health Challenges" - The American Journal of Medicine.

Considerable attention has focused on mental illness as a major contributor to homicides in the United States. Serious mental illness affects more than 14 million Americans ages 18 and older and nearly 58 million people reported having a mental illness.

Researchers find similar mental illness rates in the United States, Australia, and the United Kingdom, but notably higher gun violence in the U.S.

In 2021, 47,286 Americans died from gun violence - the highest ever - of which 46 percent were homicides and 54 percent were suicides involving firearms.

Researchers from Florida Atlantic University's Schmidt College of Medicine and collaborators compared deaths from mental illness and gun violence in the U.S., Australia and the United Kingdom and their clinical and public health challenges. Their findings were published online ahead of print in The American Journal of Medicine.

Results show that:

• In the U.S., there are approximately 393 million guns owned among the general population of about 335 million people or 1.2 guns per person.
• In Australia, there are 3.5 million guns among a population of 26.4 million or about 0.13 guns per person, likely a result of new gun laws passed in 2021.
• In 2022, the U.K. launched a successful gun reform campaign, which included banning assault weapons and handguns.

Findings also reveal that in 2019, self-reports of mental illness were 15.7 percent in the U.S., 17.6 percent in Australia and 13.8 percent in the U.K.

"The U.S. is experiencing more than 10 times higher death rates from gun violence than Australia and more than 40 times higher death rates than the U.K.," said Charles H. Hennekens, M.D., Dr.PH., co-author, First Sir Richard Doll Professor of Medicine and senior academic advisor in the FAU Schmidt College of Medicine.

"The comparisons between Australia and the U.K. indicate that mental illness is not a major contributor to the increasing trends in death from gun violence in the U.S."

The researchers suggest that the high rates of gun ownership and access to firearms and not mental illness are plausible but unproven explanations. Furthermore, they opine that if mental illness, which is similar in the three countries, played a major role in gun homicides, one would expect gun homicide rates to be comparably similar. In fact, gun homicide rates are vastly different between the U.S., Australia and the U.K.

"People with serious mental illness have a markedly reduced life expectancy of 15 to 20 percent, dying in their late 50s compared with the late 70s for the general population. They also commit suicide at about 10 times the rate of their about 1 percent prevalence in the general population and many of these suicides are due to gun violence," said Stuart Goldman, M.D., co-author, professor of psychiatry and founding program director emeritus, psychiatry residency, Department of Clinical Neurosciences, FAU Schmidt College of Medicine.

"Individuals with serious mental illness also have higher risks of committing lethal violence, however, these absolute risks are very low and result in modest contributions to societal homicides. Active, untreated symptoms appear to be the strongest risk factor as well as symptoms of substance misuse or inadequate or delayed."

The researchers also compared the rates of gun-related deaths in the U.S. by state, revealing large differences:

• Massachusetts (3.4 per 100,000)
• Hawaii (4.0 per 100,000)
• New Jersey (5.2 per 100,000)
• New York (5.4 per 100,000)
• Rhode Island (5.6 per 100,000).

Massachusetts has the lowest rates of gun ownership and deaths from gun violence in the nation. In contrast, the highest rates of gun-related deaths are:

• Mississippi (33.9 per 100,000)
• Louisiana (29.1 per 100,000)
• New Mexico (27.8 per 100,000)
• Alabama (26.4 per 100,000)
• Wyoming (26.1 per 100,000)

Moreover, the difference in the rate of gun-related deaths between U.S. states is more than six times higher than the difference in mental illness.

The researchers opine that attempts at combatting the epidemic of U.S. homicides and suicides from gun violence without addressing guns is tantamount to attempts at combatting the epidemic of deaths from lung cancer from smoking without addressing cigarettes.

About the Research Team

Study co-authors are Michelle Berglass, a pre-med student at the University of Florida; Dennis G. Maki, M.D., Ovid O. Myer Professor of Medicine, University of Wisconsin School of Medicine and Public Health; and Sarah K. Wood, M.D., director, Harvard Macy Institute, Harvard Medical School, and former vice dean, professor and chair, Women's and Children's Health, FAU Schmidt College of Medicine.

Maki and Hennekens both trained at Harvard after serving together for two years as lieutenant commanders in the U.S. Public Health Service as epidemic intelligence service (EIS) officers with the U.S. Centers for Disease Control and Prevention (CDC). They served under Alexander D. Langmuir, M.D., who created the EIS and epidemiology program at the CDC, and Donald A. Henderson, M.D., chief of the Virus Disease Surveillance Program at the CDC.

Frequently Asked Questions

NOTE: Researched FAQs by Disabled World (DW)

Does mental illness cause gun violence?

Research generally shows that mental illness accounts for only a small share of overall gun violence in society. While untreated symptoms and substance misuse can raise an individual's risk, the vast majority of people with mental illness are never violent and are more likely to be victims than perpetrators.

What role does gun ownership play in suicide rates?

Access to a firearm is strongly associated with higher rates of suicide because guns are highly lethal and allow little chance to reverse an impulsive act. In the United States, firearm suicides make up more than half of all gun deaths, which is why researchers treat gun access as a public health issue and not only a crime issue.

How did Australia change its gun laws?

Australia is widely cited for tightening firearm regulation, including buyback programs and stricter licensing, which sharply reduced the number of guns in circulation. The result is a far lower rate of gun ownership per person than in the United States, alongside markedly lower gun death rates.

Why do gun death rates vary so much between U.S. states?

State-level differences are closely linked to how many guns are owned and how strict local firearm laws are. States with lower ownership and stronger regulation, such as Massachusetts, tend to report far fewer gun deaths than states with high ownership and looser rules.

Are people with disabilities more affected by gun violence?

People with serious mental illness face a reduced life expectancy and a suicide rate far above the general population, and many of those deaths involve firearms. This makes firearm access a particular concern for advocates working to protect the health and safety of vulnerable groups.

What is the difference between a gun homicide rate and a gun death rate?

A gun homicide rate counts only deaths in which one person kills another with a firearm, while a total gun death rate includes homicides, suicides, and accidental deaths together. Distinguishing between the two matters because suicides often make up the larger portion of firearm deaths in many countries.

Insights, Analysis, and Developments

Editorial Note: The authors close with a comparison that lingers, likening efforts to curb gun homicides and suicides without addressing firearms to fighting lung cancer deaths while ignoring cigarettes. It is a deliberately uncomfortable analogy, and it lands because the data behind it is hard to wave away: three countries with comparable mental health profiles, wildly different death tolls, and a research team whose members trained at Harvard and served as epidemic intelligence officers at the CDC. Their point is not that mental illness plays no role, since untreated symptoms and substance misuse do raise individual risk, but that those risks account for only a modest share of societal homicide, and that the far larger variable sitting in plain sight is how many guns are in circulation and how easily they can be reached.

Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by Florida Atlantic University and published on 11 Dec 2023, this content may have been edited for style, clarity, or brevity.

* Editorial additions by Ian C. Langtree.