Psychopathic personality is measured with a 1970s checklist. A Berkeley psychologist says it’s time to upgrade.

If someone asked you to imagine a psychopath, who would you picture? Many of us might conjure an image of a violent criminal who will do anything without remorse to get what they want. After all, we’ve seen such a character in countless movies and other depictions over the decades.

But this isn’t the profile for everyone with psychopathic personality disorder, says Keanan Joyner, a UC Berkeley assistant professor of psychology. Rather, it describes the most extreme cases of psychopathy.

Joyner runs the Clinical Research on Externalizing and Addiction Mechanisms Laboratory, where he and his team study risk for addiction and why problematic drug use co-occurs with mental disorders. One of the disorders they study is psychopathy.

Some people who have psychopathy are likely going undetected, he says, in large part because of how it’s measured.

In a study published in the journal Psychological Assessment in June 2024, Joyner and his colleagues found that there’s a more effective system for identifying psychopathy, one of several related personality disorders that cause a lot of harm in society. It’s estimated that each year the cost of psychopathy to the U.S. criminal justice system is upward of $460 billion.

“If we understand better what these disorders are, the more that we can solve those and intervene early, the better for everyone in society,” says Joyner.

Today, psychopathic personality is measured using the 20-item psychopathy checklist, originally developed in the 1970s by Canadian psychologist Robert Hare for use in psychology experiments. The checklist looks for a range of symptoms, from superficial charm to pathological lying. It is then used as a specifier for antisocial personality disorder, rather than a standalone diagnosis, in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, or the DSM. 

Yet Joyner says there are times when a person with psychopathy might not fit the criteria for antisocial personality disorder. For example, you have to have evidence before age 15 of conduct disorder, like fire-setting or torturing animals, to be diagnosed with antisocial personality disorder.

For people with psychopathy, there’s a big reason that their misconduct might not be caught: They have a specific trait that’s largely overlooked in the current diagnostic method. This trait is central to the new system that Joyner and his colleagues propose in their study. 

A new way to measure psychopathy

To capture psychopathy’s key elements, Joyner and his team found that the 178-question Elemental Psychopathy Assessment, or EPA, based on the five-factor personality model, measures psychopathic traits more deeply than the traditional checklist. And instead of the DSM, it uses the triarchic model, which highlights three key traits that underlie psychopathy: disinhibition, which we often call impulsivity; callousness, or meanness and lack of empathy; and boldness, or lack of fear.

If we understand better what these disorders are, the more that we can solve those and intervene early, the better for everyone in society.

“The really important part of this theory, and what differentiates it, is that you now have this other dimension … that we call boldness,” Joyner says. “And this on its own is actually extremely adaptive. It actually is responsible for lack of anxiety, for sociability, for social persuasiveness and leadership capacities.”

This boldness could help explain why some with psychopathy who do engage in misconduct before age 15 might not get caught, and therefore can’t formally be diagnosed with antisocial personality disorder with psychopathic features.

Joyner says it’s important to understand that in this new method, what we think of as personality “traits” become personality “dimensions.” Rather than simply having a trait, like confidence, or not, Joyner and his colleagues measure how much or how little of it one possesses.

And instead of practitioners relying on self-reported symptoms in interviews and the psychopathy checklist, as they do currently, in the new system they also look at brain scans and how a person acts during testing.

While there’s no switch in the brain that turns on and makes a person a psychopath, Joyner says, there are neural processes that are correlated with psychopathy, like face emotion processing. If a person has a harder time processing the look of fear on another’s face, for example, it could mean that they experience less empathy. 

Psychopathy is multidimensional, Joyner says, and like in all personalities, these dimensions exist on a spectrum and are expressed in different ways. 

“If you’re asking: ‘Is my partner a psychopath? Or is my brother, friend, cousin, mother, a psychopath?’ I think that’s maybe a little bit less of an important question than: Are they psychopathic to a certain extent that it’s causing harm to other people or themselves?”

But Joyner recognizes it’s natural for humans to want to categorize things to help make sense of them. And along that vein, he says it’s OK to try to categorize psychopathy. 

What makes a psychopath?

So what, then, is the definition of a psychopath?

Joyner says a psychopath is a person who has high levels of all three personality dimensions associated with psychopathy: boldness, callousness and disinhibition.  

“That small percentage of the population is then that sinister presentation that captures the media attention so much,” he says. “It’s not like we can never say someone’s a psychopath, as long as we just remind ourselves that this is a linguistic thing. You can get high enough on these dimensions that it would be fine and accurate to say psychopath, but they still exist dimensionally.”

These personality dimensions are consistent with the most prominent theories of psychopathy, first documented by American psychiatrist Hervey Cleckley in his 1941 book, The Mask of Sanity. In the book, he writes about the role of boldness.

“He’s talking about people who, when you first meet them, actually are really likable,” Joyner says. “But as you continue to interact with them, you realize that it’s a mask of sanity, that the overall charming personality is masking a lot of dysfunction that has to do with impulsive, antisocial tendencies, actions and behaviors.”

This bold dimension of their personalities also helps explain facets of psychopathy that have confused psychologists for decades.

“Pretty early on, people were noticing that there’s this subgroup of antisocial folks who we consider psychopaths,” he says. “And what’s so odd about them is that almost every mental illness — and antisocial personality is no exception — is associated with increased risk of dying by suicide. And that makes quite a lot of sense for most mental illnesses.

“However, for this small subgroup, they were at massively decreased risk of dying by suicide. They were also at decreased risk of ever showing up to get some help with mental illness. So they weren’t help-seeking. They’re impervious. They’re self-justified. They’re bold.” 

Joyner says that people with psychopathic features, and even true psychopaths with lower antisocial dimensions to their personalities, can be very beneficial to society. In fact, they’re an essential part of humanity who, in certain contexts, help us all thrive as a species.

When psychopathic traits are useful

In the current system that we use to measure and assess psychopathy, a person with the disorder has to have a criminal history.  

But there’s nothing about criminality that’s required for psychopathy, says Joyner. In a 2012 study, psychologists ranked 42 U.S. presidents on the presence of psychopathic traits and found that those with fearless dominance, which reflects the boldness present in psychopathy, were associated with better-rated presidential performance, crisis management and leadership, among other positive traits. Another study from 2018 found that a person high in boldness is likely to find professional success, especially in sales.

But it’s not just boldness that can be beneficial. The other two traits — callousness and disinhibition — can have positive applications, as well. 

“Each of these traits on its own is actually very adaptive to have in the population,” Joyner says. “We don’t think that it’s a lack of empathy when a surgeon has to cut someone’s arm open to fix something. That’s a good, adaptive thing.” 

The same goes for disinhibition, he says. We need novelty-seekers, people who are going to take risks and explore without considering all the consequences. “Imagine back in hunter-gatherer days: If no one ever left the camp” he says, “we wouldn’t have any of this progress that we’ve enjoyed as a species.”

Further, there are some environments, Joyner says, in which being bold, callous and disinhibited is very helpful, if not necessary. 

“Our criminal justice system fails tons of people every year who are horribly socioeconomically disadvantaged, and we sequester them into unsafe sections of cities,” he says. “You put a child into that situation, and you tell them, ‘You have to walk home from school alone, because mom has to work two jobs to be able to make ends meet. And so you have to watch yourself. You have to keep yourself safe.’ For survival, it might be adaptive for them to learn to develop a bravado and to respond to aggression with some aggression to deter future aggression.”

When you remove them from that environment, though, Joyner says those traits suddenly become maladaptive, complicating our understanding of what we consider “good” or “bad” traits.

Criminality isn’t synonymous with psychopathy 

Unsafe neighborhoods across the U.S. are overpoliced, says Joyner. This makes people who live in these environments more likely to be criminalized, when others with more power in society are less likely to be caught and prosecuted. 

In 2022, Joyner published a commentary with Edelyn Verona, a professor at the University of South Florida. In their argument, they make the point that in order to accurately assess the crime cost of psychopathic personality disorder, it’s vital to include the criminal justice context.

“You know, as a Black man, I certainly can identify all of the structural situations in our country that might increase my risk of interfacing with the police,” says Joyner. 

If you are of a majority advantaged group, your crimes are less likely to be detected. Therefore, your psychopathy score would immediately be lowered by virtue of not being caught.

In Joyner’s lab, they’ve been looking at the ways in which racial dynamics in the U.S., and individual racial experiences, can creep into the measurement of things. Take the “stop-and-frisk,” program in New York City. Between the early 2000s and 2013, the NYPD recorded more than 5 million stops and frisks, of which more than half involved Black Americans.

“Black people did not have a higher rate of having cannabis or other illegal substances or something on them than white people,” he says. “But the number of Black people who were stopped and frisked was disproportionate to their size of the population.

“So now if you go by the legal involvement numbers, you have this huge proportion of Black men, in particular, who are being caught for drug use, let’s say, but they don’t actually have any higher drug use than their white counterparts.”

The same logic applies to the psychopathy checklist, Joyner says, because it doesn’t take into account the wide range of environmental factors that can determine if a person’s crime is detected or not. 

“If you are of a majority advantaged group, your crimes are less likely to be detected. Therefore, your psychopathy score would immediately be lowered by virtue of not being caught,” he says.

Joyner acknowledges that many in the scientific community don’t believe that psychopathy should be diagnosed, and that we instead need to focus on its societal harms. But he argues that, with more knowledge, we have a better chance at alleviating the damaging effects of the disorder before they become a costly problem to begin with.  

“I think that it goes toward having a functional and positive society, that we generally want people to be prosocial, to work together,” he says. “Our collaboration is the substance of what makes humans so wonderful as a species.”