What Makes a Criminal a Psychopath

The world’s notorious criminals are known for perpetrating some of the most violent, gruesome crimes, such as the serial killer Ted Bundy from the 1970s. You may have heard the terms “sociopath” and “psychopath” referred to such individuals who commit illegal and even unusual acts. Despite how loosely these labels are often used, there are key differences between sociopathy and psychopathy.

“Bundy” 2002 movie poster based on the life of the serial killer Ted Bundy

Sociopathy is a broad term that refers to an individual who has Antisocial Personality Disorder (ASPD). According to the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the standard handbook used by clinicians and psychiatrists to assess and diagnose mental disorders, ASPD is characterized by the lack of conformity to social expectations by perpetrating antisocial behaviors that disregard or violate other people’s rights (Friedman et al., 2021).

Psychopathy involves characteristics similar to ASPD. However, psychopathy is specifically defined by two factors. Factor 1 describes the emotional and interpersonal dimension of psychopathy, which refers to the core personality traits that people may often associate with psychopathy: fearlessness, boldness, excitement-seeking, absence of empathy, lack of remorse, and manipulative (Crego & Widiger, 2022; Friedman et al., 2021). Factor 2 defines the impulsive and irresponsible dimension of psychopathy, which describes the antisocial lifestyle and socially deviant behavioral aspect (Friedman et al., 2021). Although the second factor of psychopathy overlaps with the diagnostic criteria of ASPD, the first factor is not observed in all individuals diagnosed with ASPD.

Venn diagram displays the overlap between general Personality Disorder (PD), Antisocial Personality Disorder (ASPD), and Psychopathy for the sample in Baliousis et al. (2019).

In other words, most people who exhibit psychopathy also meet the criteria for ASPD, but not all people diagnosed with ASPD show psychopathic traits (Baliousis et al., 2019).

Despite criticism and numerous research studies that have identified distinctions between ASPD and psychopathy, the DSM still fails to represent the differences between them (Baliousis et al., 2019). ASPD can be formally diagnosed, yet psychopathy remains a term to describe a set of traits—not an official clinical diagnosis.

As a fan of reading and learning about true crime, which is a genre that involves the analysis of real crime cases, and a student studying neuroscience, I wondered about the neuroscience behind the actions of criminals. What is going on inside their minds to perpetrate such crimes? Who can we label as a sociopath or psychopath? Studies have suggested differences in brain structure and functioning in individuals who meet the criteria for antisocial personality disorder and those who also meet the criteria for psychopathy (Baliousis et al., 2019; Gregory et al., 2012).

Structural and functional imaging of the brain suggest the important role of the ventromedial prefrontal cortex (vmPFC) and the amygdala (Gregory et al., 2012). The vmPFC is important for moral decision making, as well as emotional thoughts and behaviors in social settings (Baliousis et al., 2019). Meanwhile, the amygdala plays a key role in emotional processing, especially for aggression and fear (Gregory et al., 2012).

View of the brain from the bottom with a red arrow pointing to the ventromedial prefrontal cortex region, and yellow arrows pointing to the amygdalae.

The connection between these two brain regions allows people to regulate their emotional reactions and behaviors to frustration and threats in the environment, particularly concerning other people’s distress (Waller et al., 2019). In a study with people at high risk for antisocial behavior, individuals who scored higher on a psychopathic traits scale had a significantly weakened connection between the vmPFC and amygdala when they viewed images of fearful faces than individuals who scored lower for psychopathic traits (Waller et al., 2019). In addition, criminals who demonstrated psychopathic traits had both reduced structural and functional connectivity of the vmPFC and amygdala than criminals who did not exhibit psychopathy (Motzkin et al., 2011).

Thus, offenders with psychopathic traits than those without psychopathic traits may have greater impairment of the vmPFC and amygdala, as well as their connectivity. Psychopaths’ absolutely fearless, remorseless traits and reactions toward other people compared to sociopaths may be explained by their inability to regulate emotions and behaviors through the vmPFC-amygdala.

Now to be clear, I am not putting the blame of criminals’ behaviors solely on the anatomy and wiring of their brains. Ted Bundy’s psychopathic crimes are inexcusable. However, it is important to consider his possibly impaired brain structure and function, especially in the vmPFC and amygdala, that may have contributed to his thoughts and behaviors toward others. The next time you come across a criminal case, it may be worth analyzing whether the perpetrator is truly a sociopath or psychopath.


Baliousis, M., Duggan, C., McCarthy, L., Huband, N., & Völlm, B. (2019). Executive function, attention, and memory deficits in antisocial personality disorder and psychopathy. Psychiatry Research, 278, 151–161. https://doi.org/10.1016/j.psychres.2019.05.046

Crego, C., & Widiger, T. A. (2022). Core traits of psychopathy. Personality Disorders: Theory, Research, and Treatment. https://doi.org/10.1037/per0000550

Friedman, N. P., Rhee, S. H., Ross, J. M., Corley, R. P., & Hewitt, J. K. (2021). Genetic and environmental relations of executive functions to antisocial personality disorder symptoms and psychopathy. International Journal of Psychophysiology, 163, 67–78. https://doi.org/10.1016/j.ijpsycho.2018.12.007

Gregory, S., Simmons, A., Kumari, V., Howard, M., Hodgins, S., & Blackwood, N. (2012). The antisocial brain: psychopathy matters: a structural MRI investigation of antisocial male violent offenders. Archives of General Psychiatry, 69(9), 962-972. https://doi.org/10.1001/archgenpsychiatry.2012.222

Motzkin, J. C., Newman, J. P., Kiehl, K. A., & Koenigs, M. (2011). Reduced prefrontal connectivity in psychopathy. Journal of Neuroscience, 31(48), 17348-17357. https://doi.org/10.1523/JNEUROSCI.4215-11.2011

7 thoughts on “What Makes a Criminal a Psychopath

  1. Hello Erica,

    I enjoyed reading your post. I was intrigued by the discussion of the weekend connection between vmPFC and amygdala in psychopaths. Some things I thought of were:

    Psychopathy is so rare that the majority of criminals are not sociopaths. Is there something else ‘wrong’ in the brains of criminals who are not psychopaths (particularly those who commit violent crimes)? Why isn’t psychopathy a clinical diagnosis in the way ASPD is?

    Great post!
    Sincerely, Bashaina (Shasha)


  2. Thank you for this blog post, Erica! I often used psychopathy and sociopathy interchangeably but from here on out I will be cautious about how I use these terms.

    Having become aware of the neuroanatomical structures that may underpin these disorders and behaviors, I wonder whether the effects can be mitigated? Also is it possible for brain injury/trauma either prenatal, during birth, or during development lead to the manifestation of psychopathy?

    Answers to these questions wouldn’t be a means of excusing the heinous crimes of people such as Ted Buddy but may help the field of neuropsychology further understand disorders and the brain-behavior relationship for disorders.


  3. Very interesting post Erica! Even as popular as movies like the Ted Bundy one is, I feel as if most people, certainly myself included, are not educated enough on the differences between a sociopath and a psychopath. In many instances, I feel like people have used these words interchangeably, and now I can certainly see that these are two very different disorders. I know you talked about the behaviors typical of a socio or psychopath, but I was wondering if there were any signs that would typically predate this? Maybe one’s that could be discovered and treated early on?


  4. As someone who enjoys forensic science and forensic psychology, I found this post very interesting. I think that you did a great job of differentiating between sociopathy and psychopathy. Additionally, I enjoyed your discussion of the brain regions associated with the two. Before reading this post, I knew about the role of the Amygdala, but had never heard about the vmPFC or the role that it plays in moral decision making. It would be interesting to look into more previous research that has been done among a population of sociopaths and psychopaths looking at the activity of the vmPFC. Overall, this was a very informative and interesting post.


  5. Hi Erica,

    From your post, I learned about the difference between sociopathy and psychopathy and I thought that these two terms can be used interchangeably. Now I realize that being diagnosed with sociopathy does not necessary mean also being diagnosed with psychopathy. I think this post is useful to help people distinguish the two personality disorders and eliminate misunderstandings on sociopathy.

    I am interested in learning about how much blame we should put on criminals with sociopathy and psychopathy. Although these criminals might have different brain structure compared with normal people (i.e., greater impairment of the vmPFC and amygdala), they have still committed crimes that hurt other people’s benefits. Should we place less moral blame on them because of their special brain structure? To what extends the judges should consider about it when deciding the punishment on these criminals?

    I think that your post has a clear logic and flows smoothly with pictures that helps with readers’ understanding. For example, the Venn chart lucidly explained the relationship between personality disorder, sociopathy, and psychopathy.



  6. Psychopaths, to me, have always initiated a certain uneasiness in me when considering their mental state. It is hard to wrap my head around the fact that we share neurological structures, yet their behavior manifests so differently from standard behavior. It is a big reason why I hate prisons systems as they do not work to address these potential neurological issues present with criminals. Instead of rehabilitating these individuals, the societal solution has been to put them away and forget about them. This can only work to worsen the mental state of these individuals.


  7. Reading this was very interesting. I learned so much about psychopathy and sociopathy. It’s crazy how outward behaviour connects tightly with the brain anatomy and wiring (and vice versa). I am often curious how a neurologist’s typical brain will react if it knows it’s in the presence of sociopaths or psychopaths, as there is a negative stigma around it. In other words, how would one’s behaviour change to others when they find out that someone is a sociopath or psychopath.
    I often like to understand psychopathy and sociopathy as sociopaths are created whilst psychopaths are born. Sociopaths are made from life traumatic experiences and can still empathise (in a limited way). Psychopaths are neurologically wired and are unable to feel empathy.

    How would the world be if everyone was highly empathetic or highly detached?


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