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Mental Illnesses: Inside the Mind of Infamous Criminals

Warning: This article may contain material that some may find disturbing so proceed with caution.

What all I’ll be talking about in this article:

  1. Introduction
  2. Mental Illnesses: Inside the Mind of Infamous Criminals
  3. Conclusion


The human brain is one of the most complex things on our planet. But things get even more complicated when we decide to understand —the mind or the conscious.

For example, let’s consider the case of serial criminals. An attempt to understand their minds or why they do things the way they do has been baffling psychologists all around the world.

And why wouldn’t they be? There is no strict answer to the above-mentioned question. Although one way by which they’ve attempted to justify their behavior is through mental illnesses. There is no denying the fact that mental illnesses have been in our society for a very long time irrespective of whether they’ve been recognized or not.

Mental illnesses are complex, understanding their true extent on a person’s behavior and actions is a mystery. In this scenario, when one has to understand the mind of a criminal and why they do certain things who are suffering from such complex mental illnesses, it becomes rather difficult. That is because we don’t understand the ratio in which both factors play a role in determining the actions of a criminal.

We have plenty and when I say plenty, I mean hundreds and thousands of cases in a single district (and many that go undiscovered) of individuals that are suffering from one or two mental illnesses and have committed some crime. It would’ve been interesting if we knew how to curb such behavior from a young age but it hasn’t been possible because of our limited knowledge on the subject.

Mental Illnesses: Inside the Mind of Infamous Criminals

Let’s look at some of the infamous criminals that suffered from mental illnesses.

Ted Bundy

The 1970s witnessed many good things but it was also the time when many cities in America witnessed record highs in a number of criminal activities but nothing could’ve prepared them for what was about to happen.

The killing spree began in the Washington district and the nearby areas, police were baffled. Who could’ve blamed them? They had never encountered such a situation — it was a time when the term “serial killer” didn’t even exist. The person who shocked the entire nation with his psychopathic actions was Ted Bundy, an appealing man who murdered tens of women.

He was a charismatic man and his way of communicating was unlike any other criminal in the past. So, when he was arrested and interrogated, police and even psychologists had a hard time getting through to him. But through constant evolution, one thing became clear — he was suffering from something called an antisocial personality disorder.

More than 50 percent of the psychologists in the University of Kentucky study also labeled Bundy as having schizoid personality disorder (SPD), which you can think of as antisocial personality disorder to the extreme.

  • Antisocial Personality Disorder [APD]

In the past, it was known as “psychopathy”, however, as awareness spread concerning mental illnesses and APD in general, it was named Antisocial Personality Disorder. Now, the basic traits include: lying, acting out violently, breaking the law, and showing no remorse. There is so much more to it but in a gist, this is what it means.

John Wayne Gacy

The case of John Wayne Gacy can send a shiver down anyone’s spine. What’s so scary about him? Well, everything. He was a man who dressed up as a clown, lured young boys into his usual lair, pretended to show a magic trick, drugged them, later proceeded to rape them, and subsequently killed them.

During his trials, the psychological evaluation determined him to be “sane” and fit to stand the trials. However, many other psychologists had different views. Taking Thomas Eliseo’s words into consideration, for example, he described Gacy as an intelligent man who apparently suffered from borderline schizophrenia. And many others believed him to be suffering from APD too.

The results were no surprise considering his rough past. In my opinion, Gacy’s case could be a perfect study to understand what’re some of the early signs in a child that could ultimately turn him so evil. Childhood is an interesting period and the mind during that time is even more fascinating as well as baffling, understanding it is no joke. We never know what will be the outcome of growing up in a certain situation, for example, two children growing up in a similar atmosphere may end up growing up completely different.

  • Borderline Schizophrenia

Borderline schizophrenia has not been formally recognized and hence, it has been difficult to completely pinpoint its symptoms. But here are some of the common characteristics present in it: delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, and diminished emotional expression.

Charles Manson

In this article, I think Charles Manson’s case is one of the most popular and it’s all thanks to his gruesome, inhumane, and satanic actions. Manson’s criminal activities have been a subject of many Hollywood movies such as The Haunting of Sharon Tate, Annabelle, Manson, and many more.

It was around the late 1960s when Manson formed his doomsday cult — the infamous Manson family. A “family” that not only listened to Manson but worshipped him, to the point of murdering people. So, how was he able to control so many people?

Manson was a sociopath, or he had Antisocial personality disorder…Manson’s actions showed how his personality disorders reflected how he treated people and what he had people do for him. Sane human beings would have the ability to feel bad about manipulating their friends.

David Berkowitz

David Berkowitz is most popularly known as the .44 Caliber Killer and the Son of Sam. His crimes shocked the entire New York City and changed the entire atmosphere of an already on the verge of breaking city. His crimes led to the once Fun City change to Fear City. His crimes were reported to have no sense or reason — just plain random killings and that’s what was so scary about him. He simply didn’t care.

His diagnosis reported him to have schizophrenia or paranoid schizophrenia.

  • Schizophrenia

According to WebMD, schizophrenia—a wide-ranging (and often misdiagnosed) mental illness—lists symptoms ranging from hallucination and delusions to emotional flatness and catatonia.

Jeffery Dahmer

Jeffery Dahmer is also known as the Milwaukee Cannibal was responsible for murdering and dismembering around 17 men and boys between the period of 1978 to 1991. He is by far one of the most mentally disturbed criminals. He was reported to be involved in necrophilia, cannibalism, and permanent preservation of body parts.

His psychological assessment report suggested that he was suffering from a borderline personality disorder and psychotic disorder.

  • Borderline Personality Disorder [BSD]

This disease is characterized by impulsive behaviors, intense mood swings, feelings of low self-worth, and problems in interpersonal relationships.


Mind in itself is so difficult to understand but when the task at hand is to understand the minds of serial killers, it becomes an almost hit and miss. It is truly a daunting task. How can one possibly imagine understanding why one decided to dismember, sodomize, or eat a person? While it is difficult their actions, psychologists believe mental illnesses to be one crucial factor. Mental illnesses are like icebergs — when you attempt to understand them, more and more uncovers.

Please note that in this article, I only discussed American male serial killers. In the next article, I will be discussing female serial killers.

Also, there are some amazing Netflix documentaries that you could watch, they’ve gone deep into the mind of some of the criminals mentioned above. Recently, the documentary on the John Wayne Gacy case has also been released.

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