Published on: Jun 3, 2019 – Latest Update: Jun 7, 2019
According to a research by Grant Duwe, Director of Research at Minnesota Department of Corrections and a Ph.D. holder in criminology, at least 59% of all mass shooters in the US during 1900-2017 had either been diagnosed with a mental disorder or demonstrated signs of serious mental illness prior to the attack.

Yet, when the NRA, gun rights groups, President Trump acknowledge mass shooting as a mental problem, the Left dismissed all evidence and came up with these headlines:
- Stop blaming mental illness for mass shootings
- Debunking the Myths: Mental Illness and Mass Shootings
- Fact-Checking 5 Myths About The Perpetrators Of Mass Shootings
Everyone is entitled to his/her own opinion obviously (as we respect the 1st amendment right). But it is important to point out the fallacies in Leftist arguments, in orders to inform open-minded gun neutrals and antis that a large part of mass shootings and gun violence are caused by mental illness.
Table of Contents
Historical Data Shows High Percentage of Mental Disorder in Mass Shooters
As mentioned in the introduction, Grant Duwe’s work, “Mass Murder in the United States: A History“, examined all 185 public mass shooting cases during 1900 – 2017 and has found at least 59% of mass shooters in the US to either had been diagnosed with a mental disorder or had demonstrated signs of serious mental illness.
Note that in his work, mass public shooting is defined as any incident in which four or more victims are killed with a gun within a 24-hour period at a public location in the absence of military conflict, collective violence or other criminal activity, such as robberies, drug deals or gang turf wars.
Grant Duwe’s work is credible, but it is rarely wise to rely on a single opinion. Here are some other research on the same subject.
- Mass Shootings: Maybe What We Need Is a Better Mental-Health Policy | Mother Jones – The research analyzed US mass shooting during 1983 – 2012 and found 38 out of 62 (61%) cases where mass shooters displayed signs of possible mental health problems prior to the killings.
- Serious Mental Illness and Mass Homicide | Treatment Advocacy Center – The percentage of mass homicides in which the perpetrator had an untreated serious mental illness varies based on many factors, such as how serious mental illness and mass killings are defined, the time period covered and other factors.
- Stop blaming mental illness for mass shootings | Vox – Only 52 out of the 235 killers in the database, or about 22%, were mentally ill. Thus, the mentally ill should not bear the burden of being regarded as the ‘chief’ perpetrators of mass murder.
- Fact-Checking 5 Myths About The Perpetrators Of Mass Shootings | Guns & America – According to the FBI report, only 25 percent of active shooters between 2000 and 2013 had ever been diagnosed with mental illness.
With these factors narrowly defined, at least 1/3 of mass killings are carried out by individuals with untreated serious mental illness.
*The varying percentage can be explained away with the difference in time period, definition of mass shooting and mental disorder.

As you can see, even with the cherry-picking of time period and definitions from the Left, they still can’t deny the significant relationship between mental illness and mass shootings because 22% and 25% are certainly not small fractions.
With these solid evidence, as high as 89% of US people, regardless of their political standing, agree on the need to prevent mentally ill people from purchasing firearms, according to a Pew Research Center survey.
But with the Left’s true goal of Total Gun Confiscation, they’re never satisfied with just keeping guns away from the mentally ill. They want all guns away from every law abiding citizen.
In the next section, we explore some of the Left’s popular argument why the mentally ill has nothing to do with mass shooting.
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Leftist Arguments and Why They’re Wrong
Here are a number of popular Leftist arguments:
- Most mentally ill are peace-loving people. They’re far more likely to be victims of violence rather than being perpetrators.
- Only 3-5% of overall US violence are committed by the mentally ill. That’s a very small insignificant portion.
- Factors such as substance abuse, childhood maltreatment and adverse social environment are more predictive of violent behaviour than mental illness.
- Psychiatrists say it’s difficult to accurately predict violence from their mentally ill patients.
- Gun is the leading cause for suicide.
We’ll go over the details of each argument and also provide counter arguments.
Most mentally ill are peace-loving people. They’re far more likely to be victims of violence rather than being perpetrators.
The Left’s Claims:
- The mentally ill are mostly victims rather than perpetrators. A study name “Risks for individuals with schizophrenia who are living in the community.” monitored 172 individuals with schizophrenia or schizoaffective disorder during 1989 – 1991 (3 years) in urban Los Angeles. Note that these 172 schizophrenia or schizoaffective disorder did not have any co-occurring substance use disorders.
- Another research paper “Mental illness and reduction of gun violence and suicide: bringing epidemiologic research to policy” also suggests high victimization rate for adults with psychotic or major mood disorders.

The study found that individuals in the sample were at least 14x more likely to be victims of violent crime than to be arrested for one.
Poorer social functioning, address changes, fewer days of medication at baseline, history of arrest and assault were significant predictors of criminal charges for these monitored individuals.
Counter Arguments:
- The Left purposefully omitted that high victimization rate is a major factor toward violent behaviour.
- That same study also suggests that the rate of any minor or serious violence during the past 12 months for people with schizophrenia, bipolar disorder, or major depression is 12% (7% for mental disorders alone with no substance abuse).
- 15% for the population without mental illness
- 33% for serious mental illness only
- 55% for serious mental illness + substance abuse combined
- According to another study, people with serious mental illness coupled with external factors of substance abuse, violent victimization history and exposure to violence in current environment has slightly more than 30% whopping probability of serious violent behaviour in the past 12 months.
According to the same study above, mentally ill subjects who were first victimized at the age later than 16 were significantly more likely to engage in violent behavior. Also subjects who were victimized both as children and later as adults were by far the most likely to behave violently toward others.
Only subjects who were victimized before the age of 16, but not revictimized afterwards, were not significantly more likely to behave violently compared to subjects who were never victimized.
This same number for persons without mental disorder nor substance abuse is just 2%.
Furthermore, first-episode psychosis patients have as high as 37% violent rate in the past 6-12 months.

The research also estimated lifetime violence rates, which are:
In this study, the mentally ill is approximately 3x more violent prone.
30% serious violent behaviour in 12 months is not exactly peace-loving.
It’s a good thing that our government recognizes and invests a substantial sum in treating people with mental illness. When these people get the medication they need, they’ll get less victimized, and in turn, conduct less violent behaviour.
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Only 3-5% of overall US violence are committed by the mentally ill. That’s a very small insignificant portion.
The Left’s Claims:
- Only 3-5% of overall US violence are committed by the mentally ill.
- In an event that all the mentally ill are fully cured by our enormous effort and resources, US violence will just go down by a tiny amount. 96% of violence will be left unaddressed. It would be a total waste of resources.
Counter Arguments:
- While the quantity of violence by mentally ill people might be low, the severity is not. Don’t forget that the mentally ill accounted for 22% – 60% of mass shootings and mass killings.
- The Left’s definition of “Overall violence” would have include punching, pushing, shoving and the likes. Not that these aren’t important, but it’s on a different level of severity to mass shooting incidents.

Indeed, mass shooting accounts for only a small fraction of gun deaths. But since many anti-guns feel emotional about it, the resource spent on preventing mass shootings could be worthwhile.
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Other factors are more predictive of violent behaviour than mental illness.
The Left’s Claims:
- Other factors such as substance abuse, childhood maltreatment and adverse social environment are more predictive of violence behaviour than mental illness.
- History of violence is currently the best single factor predictor.
Counter Arguments:
- In the particular research they cite, it explicitly says mental illness coupled with other factors would produce highly predictive profiles ranging from 2% – 30% probability of violent behaviour in the past 12 months.

A research on alcohol as a predictor of violence reveals that alcohol users have only 0.47% – 5.86% probability of violent behaviour in the past 12 months.
Thus mental illness coupled with other factors proved to be very useful in predicting violence.
Suppose they’ve done the violence profiling job properly, they’d see that typical gun owners are not a threat to anyone in the society.
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Psychiatrists say it’s difficult to accurately predict violence from their mentally ill patients.
The Left’s Claims:
- Mentally ill individuals do not recognize themselves as such. They tend to blame the outside world for their problems. Thus they are unlikely to seek a psychiatrist or would likely resist therapies.
- Even if these mentally ill individuals seek treatment, things might not improve.
- Opinions also suggest that increased stigmatization of the mentally ill could spur people to avoid seeking treatment, fearing that their medical records would enter “mentally ill databases”.
- With these reasons, focusing on the relationship between mental illness and mass shooting could yield poor results.
Michael Stone, a forensic psychiatrist at the Columbia College of Physicians, found that just about 2 out of 10 mass killers were suffering from serious mental illness. The rest had personality or antisocial disorders or were disgruntled, jilted, humiliated or full of intense rage. They were unlikely to be identified or helped by the mental-health system.
Counter Arguments:
- Most terrorists and criminals would also not recognize themselves as such. Terrorists might feel that they’re holy warriors while criminals might blame societies for all their troubles. But there are preventive measures aim at detecting terrorists and criminals before their heinous acts.
- It is clear that when mentally ill individuals seek aid at our mental health system but couldn’t get any help, our mental health system needs an upgrade.
- It might not be practical to expect psychiatrists to accurately diagnose patients by just talking with them in a 1-2 hours session. In high-risk cases, they should have access to more data points such as substance usage, criminal history, childhood treatment and all other relevant factors to make informed decisions.
We’ll just have to invest more in mental illness detection.
Inclusive data sharing between psychiatrists, polices and other government agencies would improve violent prediction from mentally ill patients. Furthermore, mental health system upgrades are needed to better detect and treat mental illness.
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Gun is a leading cause for suicide.
The Left’s Claims:
- Suicide in the US is now at an all time high compared to the last 50 years. It is the second-leading cause of death for Americans under the age of 35 and the 10th cause of death for all age groups.
- The real tragedy behind suicide deaths is that so many could be prevented. Research shows that whether attempters live or die depends in large part on the ready availability of highly lethal means, especially firearms.
- Firearms elevate suicide risk.
Firearm is the preferred suicide method, accounting for 50.6% of all suicides in 2017.
Counter Arguments:
- While firearm does increase the odds of “success” for suicidal attempts, it is just an efficient tool and is not the root cause.
- Root causes of suicide are:
- Mental disorders, especially depression and alcohol use disorders
- Breakdown in the ability to deal with life stresses, such as:
- Financial problems
- Relationship break-up
- Chronic pain and illness
- Conflict
- Disaster
- Violence
- Abuse
- Loss
- Isolation
- Discrimination
- Some countries with low firearm ownership do have higher suicide rate than the US. Here’s an example of 2017 suicidal rate per 100,000:
- US = 14
- South Korea = 26.9
- Japan = 18.5

Suicide is another topic where people with little to no exposure on guns can see how bias the anti-gun groups are. To permanently fix suicide rates, you obviously need to address issues such as mental health, economy, social and culture, not guns.
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Special Mention – Researchers’ View: A blanket prediction on the mentally ill is not fair.
According to the researchers of “Mental illness and reduction of gun violence and suicide: bringing epidemiologic research to policy”:
- Test subjects with substance use disorder (alcohol included) and serious mental illness had 10% violence rate.
- The inclusion of other demographic risk factors would improve prediction accuracy, just as it would for those in the general population without mental illness.
A blanket prediction of someone with depression and alcohol use disorder to conduct violent crime would be wrong 9 out of 10 times, an unacceptable odds which would stigmatize the mentally ill.
Counter Arguments:
- More mental illness research is needed to pinpoint the exact individual with high risk of violence.
- Blanket policies which correctly predict violent behaviour by only 10% is far from good enough.
- Much worse policies are the ones aimed at every gun owners of approximately 50 million household in 2017 (estimated by Washington Post) while there are only 61,895 gun incidents in 2017 (estimated by Gun Violence Archive, an anti-gun group). Policies like these would correctly predict violence at roughly around 0.1%.
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Recent Mass Shooters’ Mental Health
Let’s take a look at the mental health signs of recent mass shooters (as of June 3, 2019).
Note : Refer to the types of mental illness in the next section if you’re not familiar with mental health terms.
- Devon Erickson : Highlands Ranch , Colorado – May 7, 2019 – School shooting with 1 student dead and 8 injured
- Car towed from suspect’s home has ‘F*** SOCIETY’ spray painted on the side and “666” plus a pentagram sprayed on the hood.
- Expressed hatred for some Christians on one of his facebook post.
- He also wrote “I’m covered in ink and addicted to pain.” in one of his Instagram post.
- HIs mother suffered significant mental health challenges just days before the school shooting incident.
- Sources also suggest he and/or another suspect were involved in legal and illegal drug use and had been in therapy.
- A friend suggested that the mass shooter’s motive was due to his own internal struggle.
Car towed from #stemshooting suspect's home apparently has "F*** SOCIETY" spray painted on the side. Also "666" and a what looks like a pentagram sprayed on the hood. pic.twitter.com/e6QX3lq4v3
— John Fenton (@higuysimjohn) May 8, 2019
“You know what I hate? All these Christians who hate gays, yet in the bible, it says in Deuteronomy 17:12-13, if someone doesn’t do what their priest tells them to do, they are supposed to die. It has plenty of crazy stuff like that,”
- Alec Mckinney : Highlands Ranch , Colorado – May 7, 2019 – School shooting with 1 student dead and 8 injured
- On social media, McKinney tweeted angrily about STEM students : “F*CK stem kids i swear to f*cking god,”
- Referred to STEM kids with an expletive on his “finsta” account.
- Multiple sources say the shooting motive involved revenge and anger towards others at the school.
- Mckinney iss a transgender male who was in the midst of transitioning from female to male.
- Sources also suggest she and/or another suspect were involved in legal and illegal drug use and had been in therapy.
- A friend suggested that the mass shooter’s motive was due to his/her own internal struggle.
- John Earnest – Poway, California – April 27, 2019 – Shooting four people, killing one; Set a fire at an Escondido mosque
- Posted a 4,000-word anti-Semitic, Islamophobic and white supremacist manifesto online. Here are some highlights:
- “something just clicked in my mind. ‘If I won’t defend my race, how can I expect others to do the same?”
- “I do not care about the debt-based currency that Jews like to pretend is money. I do not care for the bread and circus that Jewry has used to attempt to pacify my people. I willingly sacrifice my future—the future of having a fulfilling job, a loving wife, and amazing kids. I sacrifice this for the sake of my people. OUR people. I would die a thousand times over to prevent the doomed fate that the Jews have planned for my race.”
- Claimed that European people are the victims of an ongoing genocide.
- “I did not want to have to kill Jews. But they have given us no other option. I’m just a normal dude who wanted to have a family, help and heal people, and play piano. But the Jew—with his genocidal instincts—is insistent on poking the bear until it tears his head off. The Jew has forced our hand, and our response is completely justified”
- “… My God understands why I did what I did.”
- “Every Jew is responsible for the meticulously planned genocide of the European race. They act as a unit, and every Jew plays his part to enslave the other races around him—whether consciously or subconsciously. Their crimes are endless….”
- “And finally, for their role in the murder of the Son of Man—that is the Christ. Every Jew young and old has contributed to these. For these crimes they deserve nothing but hell,”
- And many more similar stuffs …
- He was yelling that Jews were “ruining the world,” before opening fire
- He was inspired by the Tree of Life gunman along with the New Zealand mosque shooter.
- Austin Smith – Phoenix, Arizona – April 12, 2019 – Shot and killed his wife, 2 daughters and a family friend
- 5 months before the shooting, he was referred by Phoenix police for psychiatric care.
- He believed “God told him to do it”.
- Dakota Theriot – Parish, Louisiana – Jan 26, 2019 – Shot and killed 5 people
- Had been diagnosed with schizophrenia.
- Had anti-psychotic medication
- Smoked weed and drank alcohol
Suggested mental illness : Personality disorder (with substance abuse)
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Suggested mental illness : Psychotic disorder, Personality disorder
Suggested mental illness : Psychotic disorders
Suggested mental illness : Psychotic disorders (with substance abuse)
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Types of Mental Illness
Not all mental illness are created equal. Some are more violent than the other. According to WebMD, the most common types of mental illness are:
Type | Symptoms | Examples |
---|---|---|
Anxiety disorders | Respond to certain objects or situations with fear and dread. |
|
Mood disorders | Persistent feelings of sadness or periods of feeling overly happy, or fluctuations from extreme happiness to extreme sadness. |
|
Psychotic disorders | Distorted awareness and thinking such as
– Hallucinations : Experiences of images and sounds which are not real – Delusions : False fixed beliefs despite evidence to the contrary |
|
Eating disorders | Extreme emotions, attitudes, and behaviors involving weight and food. |
|
Impulse control and addiction disorders | Unable to resist urges, or impulses, to perform acts that could be harmful to themselves or others. |
|
Personality disorders | Extreme, inflexible personality traits, thinking and behaviour which significantly differ from the expectations of society. |
|
Obsessive-compulsive disorder | Plagued by constant thoughts or fears that cause them to perform certain rituals or routines. |
|
Post-traumatic stress disorder | Lasting and frightening thoughts, memories of traumatic and/or terrifying event; Often emotionally numb. | Examples of trauma
|
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Conclusion
The mentally ill exhibits:
- 3x higher violent rate than ordinary people.
- 5x-6x higher violent rate when coupled with substance abuse (alcohol, marijuana and other accessible substances included).
- Being 22% – 60% of past mass shooting perpetrators.
- 30% violence rate during the past 12 months when coupled with substance abuse, past violence abuse and current violent environment.
Yet, the Left still sees guns as the main culprit. So much for their “Common sense”.
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