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Serial Killers

A serial killer is an individual who murders a series of victims over a period of time, typically with gaps between each killing. Some serial killers kidnap and/or torture their victims prior to murdering them. While it’s not always clear what motivates serial killers to commit such heinous acts, abnormal psychological processes—notably severe antisocial tendencies—are to blame. In society, serial killers often generate fascination along with fear; their crimes tend to bring notoriety, media attention, and “fans” who study their crimes or, in some cases, form relationships with the murderer.

Understanding Serial Killers

Historians argue that serial killers have existed throughout history. In ancient and medieval times—long before the concept of a “serial killer” entered popular parlance—such murders were often thought to be the work of monsters, werewolves, or witches; when they were caught, many serial killers of the time were accused of (or even confessed to) committing the murders for "supernatural" purposes.

Though Jack the Ripper—an unidentified murderer who was active in the late 19th century—is often called the "first modern serial killer," the term “serial killer” itself was popularized in the latter half of the 20th century, when such murderers began to receive more significant media attention and drew heightened focus from increasingly sophisticated law enforcement agencies. Most of the most famous documented serial killers were active in the 20th or 21st century—coinciding both with increased public interest in serial killers’ stories, as well as with a heightened understanding of what motivates them, how they develop, and how, perhaps, their violent crimes can be prevented.

What defines a serial killer?

Most experts define a serial killer as someone who has murdered at least three people, over a period of more than a month, with at least some “cooling-off” time between each murder. Some criminal psychologists go further, arguing that serial killers must have a deviant psychological motive—for example, sexual gratification—that goes beyond the murder itself.

What’s the difference between a serial killer and a mass killer?

Serial killers and mass murderers both commit multiple homicides. However, serial killers typically commit the murders over an extended period and allow time to elapse between each. Mass murderers, by contrast, commit all their murders in a brief, one-time event. A school shooter, for instance, is considered a mass murderer rather than a serial killer.

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The Psychology of Serial Killers

Criminal psychologists, law enforcement agencies, and the general public have long been interested in what motivates serial killers to commit their terrible crimes. Because most “normal” people could never imagine doing the same, another question that draws serious interest is whether or not serial killers can be said to suffer from severe mental illness that severs their contact with reality.

But while some serial killers did appear to undergo psychotic breaks that triggered their crimes, overall, serial killers have rarely been found to be legally insane. Rather, the most consistent psychological feature among serial killers appears to be extreme antisocial behavior—they tend to lack empathy, appear incapable of remorse, show no regard for laws or social norms, and have a strong desire to revenge themselves against individuals or society at large by carrying out violent, terrifying crimes.

Are serial killers mentally ill?

It depends. Some serial killers do exhibit symptoms of psychosis, while others are diagnosed with severe bipolar disorder. However, very few serial killers are considered mentally ill enough to be declared legally insane. Rather, the majority display signs of psychopathy or sociopathy; in terms of diagnosis, they may meet the criteria for antisocial personality disorder.

Are all serial killers psychopaths?

Most serial killers demonstrate antisocial tendencies—including a lack of empathy, a disregard for laws and the rights of others, and a lack of remorse—and many meet the criteria for either psychopathy or sociopathy. Some serial killers, however, have been diagnosed with psychosis, schizophrenia, or another personality disorder, in addition to or instead of psychopathy.

Why We’re Fascinated with Serial Killers

Serial killers commit horrible crimes that should—and do—repulse us. But alongside the disgust and fear that serial killers trigger, there often exists a morbid curiosity: We want to learn more about them and examine why they do what they do. This is the case for both individuals and society as a whole; indeed, the societal fascination with serial killers can be seen in the countless books, TV shows, podcasts, and movies about serial killers, not all of which paint the murderers in a purely negative light.

But while it certainly is possible for an interest in serial killers to go too far, a fascination with evil is not inherently psychologically unhealthy. Some experts posit that interest in serial killers is fueled by our general desire to understand the unknown and to feel secure in our own lives; similarly, serial killer fascination may offer a safe outlet for dark thoughts and urges that everyone—even those who would never hurt another person—experiences.

Why am I so obsessed with serial killers?

Our brains are programmed to pay attention to calamity; an interest in serial killers fulfills this psychological need. True crime often provides an adrenaline rush that can be pleasurable when experienced in a safe environment. That serial killers tend to appear “normal” until caught can also fuel a desire to learn the “signs” so as to not be caught unawares. 

Why are there so many books, movies, TV shows, and podcasts about serial killers?

“True crime” is a popular genre, and serial killers provide prime material. This is likely because fascination with murder exists in many to some degree. Consuming such media allows someone to experience fear and horror in a controlled environment. It may also provide psychological safety or a feeling that one is armed with knowledge.

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