This Common Personality Trait May Fuel Serial Killers

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TThe ranks of serial killers seem to be rife with clinical narcissists. Dennis Rader, aka the BTK Killer, was diagnosed by a court-appointed psychiatrist as suffering from narcissistic personality disorder in part because of his intense need for fame, his self-proclaimed nickname, and his belief that he was smarter than the cops who pursued him.

And Ted Bundy has also been described by psychologists and criminologists as suffering from an extreme form of narcissism, although the infamous serial murderer and rapist was evaluated before 1980, when narcissistic personality disorder became an official diagnosis. Even Bundy’s decision to represent himself in court reflected this immense self-esteem.

But not all serial killers are the same, nor are all narcissists – and the most dangerous minds may not be those brimming with self-esteem.

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 domination, is the one we hear about most often. But another, more stealthy form of narcissism, known as the “vulnerable” subtype, has gained increasing recognition from psychologists in recent decades. Vulnerable narcissists are extremely sensitive to rejection, prone to social withdrawal, and plagued by feelings of inadequacy that can turn into resentment.

Now, a team of scientists from the University of Bamberg in Germany and the University of Essex in the United Kingdom has discovered that certain traits associated with vulnerable narcissism are much more common in sexually motivated serial killers than previously believed. The results, published in the Journal of Police and Criminal Psychologycould help investigators understand the behaviors and motivations of these offenders, which could facilitate their earlier identification, before they escalate into repeated murders.

Most previous 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 the interrogations and confessions of 45 sexually motivated male serial killers, taken from publicly available documents and private archives. They also focused more narrowly on specific narcissistic traits – such as admiration, rivalry, isolation and enmity – than on narcissistic personality disorder as a whole.

The results were striking. By systematically analyzing audio recordings of 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 self-enhancement, was exhibited by 76 percent of the men.

The results highlight a volatile combination: fragile self-esteem linked to violent aggression. This is consistent with other research that has shown that many sexually motivated killers use violence to cope with feelings of social isolation, loneliness and inadequacy.

Of course, not everyone with these narcissistic traits will turn out to be serial killers. Many vulnerable and grandiose narcissists never engage in criminal behavior. But if investigators can identify a toxic pattern earlier, perhaps they can one day stop a killing spree before it takes off.

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Main image: ffikretow / Shutterstock

• Kristen French

  Published on December 10, 2025

  Kristen French is an associate editor at Nautilus. She has worked in science journalism since 2013, reporting and writing articles and news for publications such as Wired, Backchannel, The Verge, And New York Review. She holds a master’s degree in science journalism from Columbia University.