Is There a Link Between Madness and Mass Murder?

Key Points:

• Mass murders, in which three or more people are killed by one person at one time, have long been blamed on mental illness.
• Mass shooters, in particular, are often cast as psychotic or otherwise "insane."
• But a new study of more than a century's worth of mass shootings finds that few perpetrators displayed psychotic symptoms.
• The findings could influence policy debates on mental health-related background checks for gun purchases, experts argue.

It’s been a while since a major mass murder has dominated the news. There’ve been shootings, to be sure, but the absence of large public gatherings during the pandemic seems to have discouraged personal-cause killers with big ambitions. Yet we’re still building and analyzing databases. We still hope to identify key factors for intervention and public policy decisions. One group of researchers recently provided a comprehensive analysis that corrects some negative perceptions.

The History of Mass Murder and Mental Health

Let’s look back. During the 1970s, Dr. Donald Lunde, a Stanford-based psychiatrist, examined several cases of mass murder to pinpoint the potential for intervention. At the time, he’d been in position to interview three different types of multicidal offenders in Santa Cruz, CA: mass murderer John Linley Frazier, spree killer Herbert Mullin, and serial killer Edmund Kemper. With little data, he made sweeping claims.

“Mass murderers,” Lunde wrote in Murder and Madness, “are almost always insane, and they differ in many other respects from those who kill only one person.” He divided mass murderers from sexually-compelled multiple killers and diagnosed them with paranoid schizophrenia. Frazier and Mullin were mentally unstable, as were some earlier mass killers. Yet Lunde’s broad generalization was way off the mark, along with his claim that there were no female mass murderers.

Since then, others have gathered much more data, revealing that few mass murderers have been psychotic or “insane.” Instead, they’re largely angry, rigid, and unable to cope with life’s hard knocks. They know what they’re doing and some even seek the record for fatalities. And we’ve seen female mass murderers. Priscilla Joyce Ford, for example, used her car in Reno, Nevada, in 1980, to kill 6 and injure 22.

Source: K. Ramsland

Are Most Mass Shooters Psychotic?

Recently, Brucato, Girgis, and a group of other researchers (2021) published their findings in Psychological Medicine, based on the Columbia mass murder database they developed. They believe this is the most comprehensive database to date. One goal was to learn the truth about the role in mass shootings of mental illness with psychotic features, because such crimes have “a disproportionately strong influence on society, invoking collective fear and calls for preparedness and policy changes.”

First, they sifted through 14,785 murders described in English in print or online that had reportedly occurred anywhere in the world between 1900 and 2019. Then, they identified 1,315 cases of “personal-cause” mass murder, meaning “those driven by personal motivations and not occurring within the context of war, state- or group-sponsored terrorism, gang activity, or organized crime.” (This did not include the category of spree murder, which they view as a different type of multicidal assault.)

The researchers note that the classic definition of a mass murder is four or more unlawful killings in a single event and location. Although Congress changed the definition to just three fatalities (which overlaps triple homicide), criminologists still tend to use four. Brucato et al opted for the Congressional definition of three, but added some findings for the classic definition.

Over half of mass murderers were Caucasian, and 28 percent were suicidal. The average age was 32.3. Around 65 percent had used guns. It’s likely no surprise to learn that most of the world’s mass shootings (73 percent) occur in the U.S., and that this type of assault has notably increased since the 1970s.

Psychosis Essential Reads

A First Episode of Mental Illness

Navigating Mental Crises

A significant challenge for analysis involved vagueness in the attribution to specific cases of mental illness and psychiatric disorders. From one study to another, the designation covered everything from psychosis to substance abuse to basic neuroses. The more generic the term, the higher the percentage of killers who were deemed mentally ill (up to 78 percent in some studies). To find a workable subject population, Brucato et al had to separate out the various types of disorder or disturbance. His group wanted to focus exclusively on severe mental illness with psychotic features.

They then separated out mass shooters, since this category has attracted the most media attention and generated a skewed perception of rampant mental illness. Politicians can easily claim there's little they can do about impulsive acts of madness. Yet just 8 percent of these shooters showed evidence of a true psychotic disorder. Even looking at all mass murder incidents (involving explosives, fires, vehicles, poison, or stabbing along with shooting) just 11 percent had such disorders. This is higher than the incidence in the general population but far lower than public perception might suggest. Even depression showed up in just 10 percent.

This finding runs contrary to popular belief. Psychotic shooters—those with a lifetime history of psychosis—are not running amok with assault rifles. Most, in fact, used non-automatic weapons. (It should be noted that the researchers excluded individuals in acute distress, such as those who’ve recently lost a job or loved one.)

In a press release for this article, Dr. Gary Brucato remarked, "The findings from this potentially definitive study suggest that emphasis on serious mental illness, such as schizophrenia or psychotic mood disorders, as a risk factor for mass shootings is given undue emphasis, leading to public fear and stigmatization."

The data show that the role of psychotic disturbance is less pervasive than some media suggest. These findings could impact policies for background checks for weapon purchases, as well as undermine false claims. It’s difficult to insist on severe psychiatric factors in mass shootings when an impressive body of facts shows otherwise.

The Columbia mass murder database offers a wealth of data for many different factors. Researchers who focus on mass murder events should take note.