This Common Personality Trait May Fuel Serial Killers

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The ranks of serial killers seem to overflow with clinical narcissists. Dennis Rader, aka the BTK Killer, was diagnosed by a court-appointed psychiatrist as having narcissistic personality disorder due in part to his intense need for fame, his self-appointed nickname, and his conviction that he was smarter than the cops who pursued him.

And Ted Bundy has been described by psychologists and criminologists as having an extreme form of narcissism, as well, though the infamous serial murderer and rapist was evaluated prior to 1980, when narcissistic personality disorder became an official diagnosis. Even Bundy’s decision to represent himself in court reflected this towering self-regard.

But not all serial killers are alike, nor all narcissists—and the most dangerous minds might not be the ones overflowing with self-love.

Read more: “What Makes a Narcissist?”

Narcissism comes in two main subtypes. The grandiose type, which combines a powerful need for admiration with a tendency toward aggression and dominance, is the one we most often hear about. But another, stealthier form of narcissism, known as the “vulnerable” subtype, has earned increasing recognition from psychologists in recent decades. Vulnerable narcissists are exquisitely sensitive to rejection, prone to social withdrawal, and plagued by feelings of inadequacy that can slide into resentment.

Now, a team of scientists from Bamberg University in Germany and the University of Essex, Online in the United Kingdom has found that certain traits associated with vulnerable narcissism are far more common among sexually motivated serial killers than previously appreciated. The findings, published in the Journal of Police and Criminal Psychology, could help investigators understand the behaviors and motivations of such offenders, which could make it easier to identify them earlier, before they escalate to repeated killing.

Most earlier studies of serial killers relied on individual case histories and rarely separated offenders into psychological subtypes. To build a more representative sample, the researchers behind the new study analyzed interrogations and confessions from 45 male, sexually motivated serial killers, drawn from publicly available records and private archives. They also focused more closely on specific narcissistic traits—such as admiration, rivalry, isolation, and enmity—than on narcissistic personality disorder as a whole.

The findings were striking. By systematically analyzing audio recordings of the serial killers confessions and testimonies, they found that traits linked to vulnerable enmity, including defensiveness, paranoia, and outward aggression, appeared in 84 percent of the men. Grandiose admiration, the classic showy narcissism of self-promotion and enhancement, was displayed by 76 percent of the men.

The findings point to a volatile combination: fragile self-worth tied to violent aggression. This is in line with other research that has shown that many sexually motivated killers use violence to cope with feelings of social isolation, loneliness, and inadequacy.

Not everyone with these narcissistic traits will turn out to be a serial killer, of course. Many vulnerable and grandiose narcissists never engage in criminal behavior. But if investigators can identify a toxic pattern sooner, perhaps they may one day interrupt a killing spree before it takes off.

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Lead image: ffikretow / Shutterstock

• Kristen French

  Posted on December 10, 2025

  Kristen French is an associate editor at Nautilus. She has worked in science journalism since 2013, reporting and writing features and news for publications such as Wired, Backchannel, The Verge, and New York Magazine. She has a masters degree in science journalism from Columbia University.