Popular culture descriptions of psychopathy appeal to a wide audience. Journalist and filmmaker Jon Ronson’s TED Talk on psychopathy has 24 million views as of January 2025 (TED, 2012, August 12). I often show this TED Talk to students to illustrate what popular culture gets wrong about psychopathy. In his review written in The British Journal of Psychiatry, Dr. Peter Tyrer (Reference Tyrer2012) described Ronson’s book, which formed the basis of the TED Talk, as trivializing and stigmatizing psychopathy “in the search for cheap laughs and better sales” (p. 167). Several subject-matter experts who were interviewed for the book indicated that Ronson used exaggerated or fictional accounts of their interviews (Society for the Scientific Study of Psychopathy, 2012).
Why is such an inaccurate source on psychopathy so widely viewed? Learning about psychopathy through mediums like TED Talks, True Crime podcasts, and YouTube tutorial videos is appealing because academic writing tends to be inaccessible. Academic reference books and peer-reviewed papers on psychopathy are literally inaccessible because many are behind expensive paywalls. These sources are also figuratively inaccessible because their use of jargon and technical language makes them difficult to understand. Readers who are new to psychopathy research often need to refer to multiple other sources to gain the background knowledge necessary to understand a single paper. It is also easy to come across two different papers with contradictory views on psychopathy. Although it is not problematic to have different perspectives on psychopathy, readers too often are left in the dark as to why these contradictory perspectives exist and whether one is more accurate than the other.
The fact that interested audiences are so often left in the dark with respect to the academic literature on psychopathy is disappointing because of how prominent the concept has become in criminal legal system decision-making. Dr. John Monahan, a pioneer in forensic psychology and risk assessment, noted on the cover of The Handbook of Psychopathy that psychopathy is “the most important forensic concept of the early 21st century” (Monahan, Reference Monahan2006). Part of the importance of psychopathy is based on its association with offending. The strength of this association resembles the impact of a wide range of proven interventions, such as the relationships between tutoring and academic achievement, reduced class sizes and academic achievement, and heart surgery and reductions in mortality (Hart, Reference Hart1998). In North America, the criminal behaviour of people with psychopathy traits contributes to billions of dollars in financial costs (Gatner et al., Reference Gatner, Douglas, Almond, Hart and Kropp2023). Whether rightly or wrongly, psychopathy has a major impact on decisions in the criminal legal system. To evaluate whether this influence is appropriate first requires an understanding of how psychopathy is defined.
Chapter Goals
Those interested in learning about psychopathy often face two unenviable options. The first is to read expensive, technical, inaccessible, and at times contradictory academic literature. The second option is to access popular culture sources that are often misinformed about the academic literature on psychopathy and, whether purposefully or by mistake, give an inaccurate description of what subject-matter experts mean when discussing psychopathy. My goal in writing this book is to make psychopathy research accessible without sacrificing the accuracy of the content. Readers will not receive a watered-down version of the science behind psychopathy. When technical language is unavoidable, I use case studies that illustrate complex concepts.
Making psychopathy research accessible begins with establishing a shared understanding of the construct. This chapter focuses on a very basic yet important question: What is psychopathy? Answering this question can be challenging because there is no universal definition. Thus, to have a comprehensive understanding of different perspectives, this chapter traces 200 years of discussions on psychopathy and explains how and why different definitions have emerged. A clear understanding of psychopathy is important because, in practice, the stakes associated with misattributing a person’s behaviour to psychopathy are high. The criminal legal system regularly assesses psychopathy to make decisions about a person’s future, including their freedom. Psychopathy has important real-world implications.
Due to its association with offending, psychopathy is regularly assessed to assist with decisions about sentence length, probation conditions, candidacy for treatment programs, parole decisions, jury deliberations, and, in some jurisdictions, the death penalty. To be clear, I am not advocating that psychopathy should play a role in all of these decisions. My point is that, whether right or wrong, the criminal legal system uses information about psychopathy to make decisions with far-reaching consequences. At a minimum, clear-sighted decision-making requires an understanding of what psychopathy is (and what it is not). I begin with a discussion of why definitions of psychopathy matter.
Definitions Matter
Researchers studying cancer are often interested in whether and to what extent cancer contributes to early mortality. However, fibromyalgia, anemia, pleurisy, and other illnesses have signs and symptoms that overlap with cancer and also increase the risk of mortality. The American Cancer Society (2025) has therefore taken care to develop clear definitions of various cancers. Clearly defining cancer allows doctors and clinicians to distinguish cancer from other diseases, which in turn allows researchers to have a shared understanding of cancer and make more precise conclusions about the specific contribution of cancer to mortality.
It is difficult to make precise conclusions about the contribution of psychopathy to offending if a shared understanding of psychopathy is lacking. There are major differences between how psychopathy is described in the literature produced by subject-matter expertsFootnote 1 and how it is described in popular culture. Even within the academic literature, there are some key differences in how psychopathy is defined. As mentioned by Dr. Robert Hare, the lead developer of the Psychopathy Checklist (PCL), even more troubling is the fact that subject-matter experts do not bother to provide their definition of psychopathy before describing the relationship between psychopathy and negative outcomes like violent crime (Hare, Reference Hare, Marques, Paulino and Alho2022).
The goal of this book, and this chapter in particular, is to help reduce confusion about the meaning of psychopathy. As a starting point, here is how I define psychopathy:
Psychopathy is a multidimensional syndrome, which means that it consists of the convergence of observable and subjective traits from different personality domains (Monroe & Anderson, Reference Monroe and Anderson2015).
The personality traits that comprise psychopathy mainly come from interpersonal, affective, and behavioural domains of functioning.
Core interpersonal traits are those that describe people as, for example, self-centred, entitled, and manipulative.
Core affective traits are those that describe people as, for example, detached, callous-unemotional, and unempathic.
Core behavioural traits are those that describe people as, for example, having poor behavioural control, a lack of reliability, and a tendency to be sensation seeking.
These core traits are found in both youth and adults, but the expression of these traits may differ across developmental stages. This concept is referred to as heterotypic continuity.
Psychopathy is maladaptive, meaning that the personality traits cause functional impairment in day-to-day life (e.g., negative relationships with others).
Psychopathy is dimensional (e.g., a sliding scale representing the degree of psychopathy traits) rather than categorical (e.g., a clear demarcation between psychopath and nonpsychopath).
The personality traits that define psychopathy tend to be relatively stable over time and across different social contexts.
Stability in one time period (or context) does not guarantee stability in another time period (or context).
Involvement in criminal behaviour is not a psychopathy trait.
Other descriptions of psychopathy also exist, and at least some subject-matter experts will disagree in whole or in part with how I have described psychopathy (see Debate #2 in Chapter 2). In Chapter 4, I review whether the traits I identified as core to psychopathy hold up to empirical analysis. It is not necessary for readers to adopt my definition as their own. However, providing this working definition of psychopathy is critical for developing a shared understanding of what I mean when I use the term throughout the book. In the following subsection, I explain why a shared understanding is important.
Using Definitions to Develop a Shared Understanding of Psychopathy
In the first half of the twentieth century, Austrian philosopher Ludwig Wittgenstein designed his “Beetle in a Box” thought experiment to illustrate the importance of definitions (see Wittgenstein, Reference Wittgenstein1993). Wittgenstein described a scenario with a group of people, each having their own private box that contains a “beetle.” Each person is only aware of what a “beetle” is by inspecting their own box. Nobody in the group can see inside the box of the other group members. The box could contain anything, including the same thing, something different, or even nothing at all. The term “beetle” simply represents whatever happens to be in a particular box at a particular time. Each person can freely discuss the characteristics of their beetle, but it is impossible to verify what is actually inside another person’s box. The purpose of Wittgenstein’s experiment is to illustrate that the meaning of a word can be understood by how it is used. It does not matter if each person has a different “beetle” in their box as long as each person can communicate what this beetle means to them. Similarly, it does not necessarily matter if subject-matter experts define “psychopathy” differently as long as each communicates what psychopathy means to them. Words earn their meaning through communities where there are shared rules about how to use language. These shared rules and public descriptions mean that even in the absence of a formal definition, a word like psychopathy can still have meaning, and correct and incorrect usages of the word can be identified.
Wittgenstein wanted to illustrate how people may experience pain (i.e., “the beetle”) in vastly different ways. Being open and publicly describing one’s pain helps create a shared understanding. At issue in the academic literature is the tendency for definitions and descriptions of psychopathy to be private. The private nature of psychopathy definitions has contributed to a lack of shared language. The lack of a shared language occurs even among practitioners responsible for assessing psychopathy (Shipley & Arrigo, Reference Shipley and Arrigo2001). The lack of a shared language for psychopathy is especially true when comparing academic and public communities.
By Wittgenstein’s definition, subject-matter expert definitions of psychopathy are not public. The academic literature on psychopathy is quite literally private, given that much of this literature is published in journals behind expensive paywalls. It is critical for subject-matter experts to be more public with their research on psychopathy, given how impactful expert opinions can be in changing public perceptions and attitudes (Pornpitakpan, Reference Pornpitakpan2004). The academic literature on psychopathy is also figuratively private because it uses inaccessible jargon and other dense language that is confusing to most readers, especially those who are looking to introduce themselves to psychopathy research. The private nature of academic research on psychopathy is unfortunate because there is a clear public interest in the topic. This is not a new issue; Cleckley (Reference Cleckley1976), one of the key figures in contributing to contemporary descriptions of psychopathy, noted that a major barrier to effectively addressing psychopathy traits was the general public’s lack of knowledge (p. 31).
Despite public interest, only 15 percent of laypeople report learning about psychopathy through academic sources (Ostapchuk, Reference Ostapchuk2018). This is unfortunate given that experimental research shows that exposing laypersons to clear descriptions of psychopathy can help debunk myths that create stigma about psychopathy as a mental health disorder (Ostapchuk, Reference Ostapchuk2018). People are far more likely to report that their understanding of psychopathy is based on intuition or popular culture sources. Journalist and filmmaker Jon Ronson’s TED Talk on psychopathy has over 24 million views on YouTube. Ronson’s description of psychopathy is accessible and, to some, entertaining (TED, 2012, August 12). Although I take issue with Ronson’s depiction of the academic literature on psychopathy, he at least satisfies Wittgenstein’s emphasis on making his definition of psychopathy public. I can point out the aspects of Ronson’s depiction of psychopathy that I disagree with. The academic literature’s failure to publicly express its views on psychopathy means that audiences are unable to identify instances in which Ronson’s description of psychopathy conflicts with academic descriptions of psychopathy. As will become clearer in Chapter 2, Ronson’s description of psychopathy is, at best, an inaccurate representation of the academic literature. At worst, Ronson’s TED Talk is disingenuous storytelling. Subject-matter experts must accept responsibility here. Audiences who are new to the concept of psychopathy cannot be expected to identify incorrect descriptions of academic definitions of psychopathy. Such an expectation is especially unreasonable when academic descriptions of psychopathy remain both literally and figuratively private.
To reiterate, making academic research on psychopathy more public and less private and more accessible and less inaccurate does not require the development of a universally agreed-upon definition of psychopathy. In fact, universal definitions of a phenomenon can be problematic. As Wittgenstein noted, absolute or fixed definitions give the impression that “some thing” is “one thing.” Psychopathy is polysemous; it refers to different ideas both within and outside of academic and clinical settings. Moreover, descriptions of psychopathy evolve over time. If good science is self-correcting, then revisiting descriptions and revising measures of psychopathy in light of new information should be encouraged (Skeem & Cooke, Reference Skeem and Cooke2010). Subject-matter experts can be more public about their work by writing for The Conversation and other outlets designed to communicate scientific research. TEDx Talks, media interviews, and using social media are a few examples of how to improve knowledge mobilization.
Academic Pessimism Regarding Psychopathy
The failure of subject-matter experts to communicate the meaning of psychopathy has also led to skepticism in some academic circles regarding the existence or meaningfulness of psychopathy and the methodological rigor of psychopathy research (Maruna, Reference Maruna2025). Subject-matter experts too often have made flippant claims about psychopathy, including that it factors into all crime (DeLisi, Reference DeLisi2016) and that it is untreatable (Harris & Rice, Reference Harris, Rice, Herve and Yuille2017). Such claims have been glommed onto by other academics who do not read the psychopathy literature more fully or seemingly ignore other psychopathy research if it does not fit their desired narrative. In this case, the desired narrative is to depict psychopathy research as biased and lacking in rigour. For example, some writers have overlooked a substantial body of recent research showing that psychopathy traits can change over time (e.g., Hawes et al., Reference Hawes, Mulvey, Schubert and Pardini2014; McCuish & Lussier, Reference McCuish and Lussier2021) and instead concluded that mainstream psychopathy research denies the possibility of change among people with psychopathy traits (American Society of Criminology, 2024; Larsen, Reference Larsen2025; Maruna, Reference Maruna2025).
If the meaning of psychopathy cannot be communicated clearly, why should anyone believe that it exists? Edwin Sutherland, whose training was in sociology and who became one of the pioneers of criminology, rightfully criticized psychiatrists for discussing psychopathy without addressing how to measure the construct in a reliable way (Sutherland, Reference Sutherland1949). Similarly, given the lack of reliable and valid measures Tennenbaum (Reference Tennenbaum1977) questioned the value of constructs like psychopathy to the study of criminal behaviour. From Sutherland’s perspective, the definition of psychopathy seemed to vary from one psychiatrist to the next and was, in effect, used as a multipurpose tool that allowed a person’s difficult behaviour to suddenly be understood and explained. In effect, resembling Wittgenstein’s beetle in a box experiment, each psychiatrist was confined to looking inside their own psychopathy box without considering how others described psychopathy.
Sutherland and Tennenbaum’s criticisms had a lasting impact on sociologists’ and criminologists’ perspectives on psychopathy.Footnote 2 For example, at the 2023 American Society of Criminology Conference in Philadelphia Pennsylvania, the largest criminology conference in the world, then-President Dr. Shadd Maruna delivered his Presidential Address to conference attendees (see American Society of Criminology, 2024Footnote 3). As part of this address, Dr. Maruna posited that psychopathy was essentially a disorder “invented in the 1990s in academia” by a group of Canadians on the fringes of forensic psychology who brought this “bizarre idea” into mainstream psychology. Dr. Maruna’s framing of psychopathy as a Canadian idea that exists on the fringes of psychology contrasts with the fact that there are dozens of translations of psychopathy measures that are used throughout the world (Hoff et al., Reference Hoff, Rypdal, Hystad, Hart, Mykletun, Kreis and Cooke2014). As illustrated in the following sections, at odds with Maruna’s claim that psychopathy was “invented in the 1990s in academia” (American Society of Criminology, 2024) is the fact that descriptions of psychopathy date back thousands of years.
Early Descriptions of Psychopathy
Descriptions of psychopathy traits emerged centuries before the term “psychopathy” entered the daily language of forensic psychologists. For example, Theophrastus (371–287 BCE), a student of Aristotle, described the “unscrupulous man” as manipulative and unrepentant. Yildrim (Reference Yildrim2015) provides an excellent historical tracing of psychopathy’s conceptual origins. Psychopathy traits have been described in Shakespeare plays (e.g., Aaron the Moor in Titus Andronicus). The idea of psychopathy traits is not just a Western phenomenon. The Yoruba people in Nigeria use the term “Arana Kan” to describe someone who is malicious, bullheaded, and defies others. The term “kulangeta” is used by Yupik-speaking Inuit Peoples to describe people who persistently lie, steal, cheat, and know that what they are doing is wrong but simply do not bother to change (see Kiehl, Reference Kiehl2015). The term “psychopathy” may have been “invented” by researchers, but that does not make the traits that underscore the psychopathy construct any less real.
French psychologist Philippe Pinel (1745–1826) is credited with providing one of the first formal attempts to describe psychopathy. Pinel used the term manie sans délire to describe people whose problem behaviour (manie) occurred without (sans) the presence of delusions (délire). Pinel used this term to describe people who were aware that they were engaging in harmful behaviour but simply did not care. This contrasted with much of the prior work in psychiatry that aimed to identify disorders in which people were either entirely unaware of their behaviour or unaware that their behaviour was wrong or causing harm. American psychiatrist Benjamin Rush (Reference Rush1812) suggested that because people were aware of, but ultimately morally unconcerned by, their own behaviour, it was of religious and legal importance to have psychiatry assist in the treatment of psychopathy (see Millon et al., Reference Millon, Simonsen, Birket-Smith, Millon, Simonsen, Birket-Smith and Davis1998). Psychiatrists like Pinel and Rush viewed people with psychopathy traits as morally ambiguous (e.g., lacking remorse). Pinel and Rush believed that people were born with these traits and, in the absence of intervention, would remain indifferent regarding the impact of their behaviour.
British psychiatrist J. C. Prichard had a much different perspective than Pinel and Rush. He believed that people with psychopathy traits enjoyed harmful behaviour and therefore described the psychopath as morally deplorable. Whereas Pinel and Rush called for medical intervention rather than incarceration, Prichard called for severe social and legal punishment (see Toch, Reference Toch, Millon, Simonsen, Birket-Smith and Davis1998). This description of Prichard’s perspective is not intended as an endorsement. Rather, it illustrates the type of unsubstantiated claim about psychopathy from certain psychiatrists that Sutherland later criticized.
German scholar Julius Koch (Reference Koch1892) was perhaps the first to use the term psychopathy (“psychopathische”). He used this term to describe the “suffering soul.” Critical to informing contemporary definitions of psychopathy was Koch’s emphasis that psychopathy traits were stable over the life-course and consistent across social situations. Ultimately, descriptions of psychopathy traits by Koch, Prichard, Rush, and Pinel received criticism for being overly broad. Under these descriptions, essentially any deviation from reason or morality was viewed as an indicator of psychopathy (Ellard, Reference Ellard1988).
The path from Pinel to contemporary descriptions of psychopathy that inform twenty-first century research hardly followed a straight line. Whereas psychiatrists like Pinel and Koch emphasized personality dimensions of psychopathy, psychiatrists of the early twentieth century tended to use the construct of psychopathy as an amorphous placeholder for classifying abnormal behaviour, especially sexual offences (Lussier et al., Reference Lussier, McCuish and Cale2021; Veal & Ogloff, Reference Veal, Ogloff, Marques, Paulino and Alho2022). In contrast to twenty-first century research, which often uses psychopathy to understand criminal behaviour, twentieth-century research tended to use atypical criminal behaviours to describe psychopathy. In this earlier era, it was not the personality traits of the patient that led to a psychopathy diagnosis, but rather the nature of the behaviour that was perpetrated. In the early twentieth century, certain psychiatrists and political figures used this view of psychopathy to justify eugenics, including the forced sterilization of patients treated for psychopathy (Rafter, Reference Rafter1997). German psychiatrist Richard von Krafft-Ebing (Reference Krafft-Ebing and Chaddock1904) described people with psychopathy traits as “morally depraved” and “savages.” He felt that the answer to psychopathy was social condemnation, ostracism, and long-term incarceration (see Arrigo & Shipley, Reference Arrigo and Shipley2001; Toch, Reference Toch, Millon, Simonsen, Birket-Smith and Davis1998). The tendency for the True Crime genre of the twenty-first century to describe psychopathy in the same way that it was described during the eugenics movement of the twentieth century is a major reason for my pushback against popular culture’s representation of the academic literature on psychopathy.Footnote 4
By the mid-twentieth century, perspectives on psychopathy shifted away from punishment and condemnation and back toward a focus on treatment. Although this may sound like a progressive approach, treatment strategies of this era were far from humane (see Chapter 2). Although there was more of a focus on treatment, psychiatrists continued to get things backward by focusing on the crime committed to make a diagnosis of psychopathy. For example, Sexual Psychopath Laws were created in the mid-twentieth century to give courts the power to label a person a psychopath if their offence was of a sexual nature (Karpman, Reference Karpman1948). Koch’s emphasis that psychopathy was defined by personality traits was not reflected in these laws. Similarly, Pinel’s emphasis on how people with psychopathy traits were aware of their behaviour was forgotten and replaced with the view that the sexual psychopath had little or no control over their behaviour (Roth, Reference Roth1952).
Psychiatrists tended to ascribe the psychopathy label to people whose behaviour did not fit within social convention. Sociologists were especially critical of psychiatry’s tendency to pathologize any sign of perceived dysfunction, including homosexuality, hysteria, divorce, and both over- or under-participation in social affairs (Becker, Reference Becker1963). Psychiatrists were often concerned with less severe forms of social deviancy because cases of extreme violence or perversion were thought to be preceded by these less serious behaviours. Unfortunately, psychiatrists overlooked an obvious but critical question. Specifically, how often do people involved in minor forms of perceived social deviancy go on to perpetrate acts of extreme violence? This issue, referred to as a false positive error, pervaded psychiatry and psychology research for decades. In reality, people involved in minor forms of social deviance rarely escalated to more harmful behaviours.
In sum, although nineteenth-century descriptions of psychopathy focused on personality traits, the early ideas of Pinel and Koch were co-opted in the early twentieth century. Psychopathy became a device used by psychiatrists to label certain unwanted or atypical behaviours. It took nearly half a century to realign the focus of psychopathy research with its conceptual roots.
The DSM and Its Failed Attempt to Clarify Psychopathy as a Mental Disorder
To address concerns about broad, vague, and subjective descriptions of mental disorders, the American Psychiatric Association created the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM is referred to as “the bible of US psychiatry” (Pickersgill, Reference Pickersgill2012, p. 544) and includes sections on how to use the manual, diagnostic criteria for different conditions, and on emerging measures and models, including attention to how cultural differences might impact assessment. The first version of the DSM was developed in 1952, and although it was not developed specifically to resolve issues with inconsistencies in the description of psychopathy, one of its goals was to reduce conceptual drift. Specifically, it was recognized that how psychopathy was described by Pinel and Koch differed from how psychiatrists later applied the concept (e.g., creation of Sexual Psychopathy Laws) as a catch-all category for socially undesirable or aberrant behaviour (Karpman, Reference Karpman1951).
Psychopathy, Sociopathy, and Antisocial Personality Disorder in the DSM
I am about to describe a relatively confusing history of how the terms psychopathy, sociopathy, and antisocial personality disorder have been used. To reduce confusion, it may be helpful to keep in mind that these three terms,Footnote 5 at least in my view, do not represent three different disorders. Over the history of the DSM, three different terms have been used, all of which were intended to describe the same disorder characterized by maladaptive personality traits. Where the terms differ is with respect to (1) the level of detail with which they describe personality traits and (2) the importance given to criminal behaviour as a defining feature of the disorder. This reflects a problem, not just with the DSM, but with a failure by subject-matter experts to address confusion about psychopathy, sociopathy, and antisocial personality disorder. This inconsistency has created confusion not only among jurors and other laypeople but even among subject-matter experts. For example, professionals tasked with assessing psychopathy have reported experiencing challenges in their forensic practices due to changing definitions and opinions on psychopathy (Arrigo & Shipley, Reference Arrigo and Shipley2001).
The DSM-I and DSM-II used the term sociopathic personality disturbance to reflect Dr. Hervey Cleckley’s (Reference Cleckley1941, Reference Cleckley1976) description of psychopathy in his groundbreaking book, The Mask of Sanity.Footnote 6 Cleckley’s book was a response to vague descriptions of psychopathy that dominated the first half of the twentieth century. Cleckley’s book aligned with the DSM’s overarching goal of formalizing the definition of disorders like psychopathy. In line with Pinel and Koch, instead of defining psychopathy by the presence of abnormal criminal behaviour, Cleckley’s description focused on maladaptive personality traits, such as callous disregard for others. It is not entirely clear why the DSM borrowed so heavily from Cleckley’s description of psychopathy yet decided to use an entirely different term in sociopathic personality disturbance. One possibility is that the DSM-I and DSM-II emphasized that sociopathic personality disturbance included persistent involvement in antisocial behaviour. Thus, sociopathic personality disturbance included descriptions of psychopathic personality traits but also included the consequences of these traits.
In the 1970s, the American Psychiatric Association initiated a major overhaul of the DSM. This overhaul included removing all references to sociopathy as a clinical construct. The DSM-III replaced sociopathic personality disturbance with antisocial personality disorder. The change in name, despite an effort to capture the same concept, is similar to how Coca-Cola replaced “old Coke” with a slightly sweeter version of “new Coke” in 1985 (only to return to “Classic Coke” shortly thereafter). Antisocial personality disorder was meant to reflect the same construct as psychopathy/sociopathic personality disturbance. However, in the eyes of many researchers, antisocial personality disorder failed to capture Cleckley’s focus on personality traits.
Dr. Lee Robins spearheaded the transition from sociopathic personality disturbance to antisocial personality disorder. Part of the goal of the DSM-III was to develop more objective methods of measuring disorders. Although this goal was reasonable in principle, Robins’ efforts to make the assessment of psychopathy more reliable resulted in stripping away the consideration of personality traits, which were previously considered core components of psychopathy. For example, Cleckley’s description of psychopathy emphasized that traits such as a lack of remorse were key indicators of the construct. Such traits were accounted for in DSM-I and DSM-II descriptions of sociopathic personality disturbance. Robins believed that it would be difficult for psychiatrists from different jurisdictions to reliably assess emotional traits like remorse. Therefore, such traits were removed from the criteria for antisocial personality disorder. Robins believed that histories of antisocial and criminal behaviour could be assessed more objectively and reliably, and thus such behaviours were prioritized in the definition of antisocial personality disorder/psychopathy. Before being quick to judge Robins’ decision, keep in mind the state of psychology and psychiatry at the time. Critics like Sutherland questioned the subjective decision-making of psychiatrists. Robins’ revisions addressed concerns about vague and broad descriptions of disorders by moving the measurement of antisocial personality disorder/psychopathy toward more objective criteria.
Antisocial personality disorder, which remains in the most recent version of the DSM (DSM-5), in essence reflects a watered-down version of psychopathy. Criteria for antisocial personality disorder are as follows (see DSM-5 for precise descriptors):
The individual must be at least 18 years of age at the time of assessment.
Evidence of at least three forms of antisocial or criminal behaviour occurring since age 15, including participation in illegal acts, aggressive behaviour, irresponsible behaviour, and lack of remorse.
Evidence of at least three forms of antisocial or criminal behaviour prior to age 15, including frequent bullying, frequent fighting, cruelty to animals, cruelty to people, and sexual behaviour problems.
Behaviours are not occurring during expressions of symptoms of schizophrenia.
Measuring antisocial personality disorder using indicators proclaimed to be more objective came at a cost. Similar to the difference between a cold and pneumonia, the measurement criteria for antisocial personality disorder (a cold) are effectively a watered-down version of psychopathy (pneumonia). Only about one in three people who meet the criteria for antisocial personality disorder also score high on contemporary measures of psychopathy (e.g., PCL-R).Footnote 7
Researcher Opposition to Antisocial Personality Disorder
Several subject-matter experts disagreed with Robins’ decision to emphasize behavioural characteristics of psychopathy in the DSM’s description of antisocial personality disorder. Shipley and Arrigo (Reference Shipley and Arrigo2001) questioned how the DSM could claim that antisocial personality disorder adequately reflected the psychopathy construct when most of the core personality traits that define psychopathy were ignored by the DSM criteria. Millon (Reference Millon1981) argued that the criteria for antisocial personality disorder were overly inclusive. Too many people would be identified as having antisocial personality disorder/psychopathy. For example, Michael, discussed in the Preface of this book, represents the type of person who might be classified as a psychopath if the focus were mainly on behavioural characteristics. Millon felt that ignoring personality characteristics meant that antisocial personality disorder criteria failed to clarify why criminal behaviours were being perpetrated in the first place and thus would not be helpful for guiding treatment. Similarly, Gacono and Hutton (Reference Gacono and Hutton1994) acknowledged that the unique traits of psychopathy that were important for understanding the development of criminal behaviour had been excluded from the DSM’s description of antisocial personality disorder.
Hart and Hare (Reference Hart, Hare, Stoff, Breiling and Maser1997) raised concerns that DSM-III criteria for antisocial personality disorder were not selected based on empirical evidence of their ability to predict future criminal behaviour. There was also no empirical basis for the decision to require at least three behavioural indicators and to distinguish between indicators occurring before vs. after age 15. Why three behavioural indicators and not four? Why age 15 and not age 14? In effect, psychopathy’s rebranding from sociopathic personality disturbance to antisocial personality disorder was not driven by scienceFootnote 8 but by a desire for simplicity. The behavioural criteria for antisocial personality disorder also exhibit substantial redundancy. For example, engaging in sexually coercive behaviour before age 15 could also be viewed as a form of criminal behaviour, a form of bullying, and a form of cruelty to others.
Reviewing the DSM’s Contribution to Psychopathy Descriptions
To summarize, in theory, sociopathic personality disturbance and antisocial personality disorder are not different constructs. Nor are they, in theory, different from psychopathy. At different times, the DSM has used sociopathic personality disturbance and antisocial personality disorder as clinical concepts meant to represent psychopathy. Different names for the same thing.
Reference to sociopathic personality disturbance essentially has been extinguished from academic research on psychopathy for nearly half a century. Reference to sociopathy is found almost exclusively in popular culture, where it is used as a tool to identify people who persistently engage in antisocial behaviour. Unfortunately, such usages have misled audiences into believing that sociopathy is a clinical term with contemporary importance and distinct from psychopathy. For example, in the BBC television series Sherlock Holmes, the titular character claims that they are not a “psychopath” but rather a “high functioning sociopath” and that it is important to “know the difference.” The difference, in the mind of Sherlock and others,Footnote 9 is that psychopathy has a genetic cause, whereas sociopathy has an environmental cause. In reality, contemporary academic literature rarely references sociopathy and certainly does not contrast psychopathy with sociopathy. Despite the persistence of discussions of sociopathy, even in science-promoting blogs (Jewell & Raypole, Reference Jewell and Raypole2024), reference to sociopathy has disappeared from the DSM. The term has also disappeared from the research agendas of subject-matter experts. For example, the term psychopathy appeared in the 2024 American Psychology-Law Society Annual Conference Program on 90 occasions. Sociopathy/sociopathic personality disturbance was not mentioned once. In the academic literature, research on sociopathic personality disturbance has effectively gone by the wayside.
In addition to sociopathy, antisocial personality disorder is commonly used to refer to psychopathy. After stripping away references to personality trait indicators of psychopathy, antisocial personality disorder, as originally defined in the DSM-III, effectively described people who were chronically involved in antisocial behaviour. The DSM-III intended for antisocial personality disorder to reflect psychopathy, just not the personality-based version of psychopathy described by Cleckley and others. Lynam and Vachon (Reference Lynam and Vachon2012) argued that the DSM missed an opportunity to unify the constructs of psychopathy and antisocial personality disorder by allowing the description of these two constructs to drift apart.
In sum, antisocial personality disorder was, in theory, intended to represent psychopathy. However, the criteria used to measure antisocial personality disorder provide such limited coverage of psychopathy traits that, in practice, it makes very little sense to consider psychopathy and antisocial personality disorder as two names for the same thing. It is noteworthy that subject-matter experts with different perspectives on core traits of psychopathy nevertheless agree that DSM-based definitions of antisocial personality disorder have conceptually drifted substantially from definitions of psychopathy (Haslam, Reference Haslam2003; Lynam & Vachon, Reference Lynam and Vachon2012; Millon, Reference Millon1981).
Contemporary Descriptions of Psychopathy
With the DSM’s use of antisocial personality disorder only scratching the surface of psychopathy traits,Footnote 10 subject-matter experts have developed their own descriptions and measures of psychopathy. Virtually all contemporary descriptions of psychopathy were heavily influenced by Cleckley’s book, The Mask of Sanity. In this section, I begin by describing Cleckley’s version of psychopathy. I explain how Cleckleyan psychopathy remains one of the dominant contemporary perspectives on psychopathy. I also discuss three other perspectives that, although clearly influenced by Cleckley, also have unique characteristics that have resulted in distinct contributions to how psychopathy is measured and researched in the twenty-first century.
The Mask of Sanity as a Foundation for Contemporary Research on Psychopathy
In his book, Cleckley used a series of case studies from his experience working with psychiatric patients to emphasize four main characteristics of psychopathy. These characteristics are central in virtually all contemporary descriptions of psychopathy.Footnote 11 First, psychopathy manifests in a wide range of social domains, including interactions at school, work, with family, friends, and intimate partners. The assessment of psychopathy, therefore, should not be restricted to a person’s criminal interactions. Second, psychopathy requires an examination of a person’s thoughts, feelings, attitudes, and behaviours. This implies that interviews are essential for assessing a person’s emotions and views toward people. This second characteristic of psychopathy was disregarded by Robins when developing the criteria for antisocial personality disorder. Third, psychopathy is a multidimensional construct. This means that psychopathy is the manifestation of multiple traits from different domains of personality functioning that come together to form the overarching construct. Fourth, because psychopathy includes subjective indicators of personality traits,Footnote 12 nuanced and comprehensive measures were needed. Cleckley (Reference Cleckley1976, pp. 28–29) was clear that the measurement of psychopathy was complex and required consideration of traits from multiple domains.
Cleckley did not address his own call to develop nuanced measures of psychopathy. However, he left a detailed map for others to follow.Footnote 13 Through case studies of his former patients, Cleckley identified 16 traits spanning interpersonal, affective, and behavioural domains of functioning. Interpersonally, Cleckley defined psychopathy by manipulative, superficially charming, and manipulative traits. Affectively, Cleckley viewed a lack of remorse, empathy, and connectivity to others as the prototypical features of psychopathy. Affective traits included a lack of emotional depth beyond the superficial, figuratively implying that psychopathy includes an ability to hear, but not feel, the music (i.e., semantic aphasia). Behaviourally, he described psychopathy as involving socially disruptive and antisocial behaviour. Although some of Cleckley’s patients were involved in criminal behaviour, evidence of prior involvement in criminal behaviour was not viewed as essential to the assessment of psychopathy (Arrigo & Shipley, Reference Arrigo and Shipley2001).
It was not until several decades after Cleckley’s description of psychopathy that researchers attempted to systematically measure Cleckley’s version of psychopathy. Robert Hare and David Cox (Reference Hare, Cox, Hare and Schalling1978) initiated the formal measurement of Cleckley’s definition of psychopathy by developing a “7-point scale of psychopathy, the conceptual framework for the ratings being typified best by Cleckley’s (Reference Cleckley1976) The Mask of Sanity” (Hare, Reference Hare1980, p. 111; emphasis in original). This preliminary scale marked the starting point for the development of the PCL, and then, after a period of refinement, the Psychopathy Checklist – Revised (PCL-R; Hare, Reference Hare2003). The PCL-R consists of 20 items, each scored on a three-point scale, that measure deficits in interpersonal, affective, behavioural, and antisocial domains of functioning. These items are rated by experts who have been trained in the assessment of psychopathy. Although the PCL-R is the most widely-used measure of psychopathy and often described as the gold standard, it is important not to conflate the PCL-R with psychopathy. As Gatner (Reference Gatner2019) pointed out, “a PCL-R score is not psychopathy any more than an intelligence test score is intelligence itself” (p. 5). The most common criticism of PCL measures (there is also a screening version and a youth version) is their inclusion of items reflecting involvement in criminal behaviour, which marks a drift from Cleckley’s description of psychopathy (Skeem & Cooke, Reference Skeem and Cooke2010). Hare has responded to these criticisms on multiple occasions (see Chapter 2), and has argued (Hare, Reference Hare, Marques, Paulino and Alho2022) that the field should not be too quick to universally accept Cleckley’s definition of psychopathy. Just as a single measure of psychopathy should not be confused with psychopathy, Cleckley’s description of psychopathy should not be regarded as the universal truth about psychopathy.
Although not accepted as a universal definition, Cleckley’s description of psychopathy, in addition to influencing the development of PCL measures, has helped form the basis of three additional major perspectives on the definition of psychopathy. Table 1.1 summarizes the extent to which these perspectives converge and diverge on key points. If there was any doubt as to Cleckley’s contribution to contemporary descriptions of psychopathy, Westen and Weinberger (Reference Westen and Weinberger2004) summarized his work as follows (p. 599):
Virtually all current research on psychopathy presupposes the observations of a brilliant clinical observer [Cleckley, Reference Cleckley1941/Reference Cleckley1976] whose clinical immersion among psychopaths over 60 years ago still provides the foundation for the measure [the PCL-R] considered the gold standard in psychopathy research.
| Definition | Key measure | View of successful psychopathy | Structure of psychopathy | Criminal behaviour as indicator of psychopathy | Key traits |
|---|---|---|---|---|---|
| Cleckley | PCL Family (Expert Rating) | Possibly | Multidimensional; additive | Possibly | Affective personality traits† |
| Comprehensive Assessment of Psychopathic Personality (CAPP) | CAPP Interview (Expert Rating); CAPP Self-Report | No | Multidimensional; additive | No | Self-centred, manipulative, unempathic†† |
| Triarchic model | Psychopathic Personality Inventory – Revised (PPI-R), Triarchic Psychopathy Measure (Tri-PM) (Self-Report) | Yes. Boldness provides a mask of sanity | Sometimes treated as multidimensional; Orthogonal | No | Boldness, meanness, disinhibition††† |
| Extreme version of general personality | Elemental Psychopathy Assessment (Self-Report) | Possibly | Multidimensional; additive | No | Unspecified |
Notes.† Cleckley (Reference Cleckley1976); ††Hoff et al. (Reference Hoff, Rypdal, Mykletun and Cooke2012); ††† Patrick (Reference Patrick, Salekin and Lynam2010a).
The Triarchic Model of Psychopathy
The triarchic model of psychopathy was developed based on a review of theoretical and clinical descriptions of psychopathy, including Cleckley’s work, as well as empirical research on psychopathy. This model proposes three dimensions of psychopathy: boldness, meanness, and disinhibition (Patrick, Reference Patrick2010b). Meanness and disinhibition reflect the affective and behavioural traits of psychopathy described by Cleckley. Two features of the triarchic model distinguish it from other contemporary descriptions of psychopathy. I discuss these in greater detail in Chapter 2. First, the triarchic model is distinct because of its emphasis on boldness as a defining feature. Boldness refers to the processes that allow a person to be manipulative or dominant over others or deceive others without any anxiety or nervousness (Patrick, Reference Patrick2022). Patrick (Reference Patrick, Salekin and Lynam2010a, Reference Patrick2018) argued that boldness allows individuals to adopt the “mask of sanity” described by Cleckley. Dr. Scott Lilienfeld and others have suggested that boldness reflects Cleckleyan psychopathy descriptions of fearlessness that allow someone to lie without anxiety (Lilienfeld et al., Reference Lilienfeld, Smith, Sauvigné, Patrick, Drislane, Latzman and Krueger2016).
A second way in which the triarchic model is distinct from other descriptions of psychopathy is its suggestion that psychopathy can be an adaptive construct. This means that psychopathy may contribute to positive social and life outcomes, including associations with prosocial peers, higher levels of resiliency, and fewer internalizing problems like depression (see Dotterer et al., Reference Dotterer, Waller, Cope, Hicks, Nigg, Zucker and Hyde2017). Patrick et al. (Reference Patrick, Drislane and Strickland2012) specifically focused on the role of boldness as an adaptive trait that allowed people to act without fear. Most other descriptions, by contrast, emphasize that psychopathy is a maladaptive personality disorder that influences negative life outcomes.
Measures of psychopathy based on the triarchic model include the PPI-R (Lilienfeld & Widows, Reference Lilienfeld and Widows2005) and the Tri-PM; (Patrick et al., Reference Patrick, Fowles and Krueger2009). Unlike the PCL-R, which requires a trained professional to conduct an interview and score the instrument, the PPI-R and Tri-PM are self-report instruments completed via a pencil-and-paper survey. Respondents rate a series of statements on a Likert scale (e.g., from “strongly disagree” to “strongly agree”). Research on the PCL generally reports positive correlations between interpersonal, affective, and behavioural traits (McCuish et al., Reference McCuish and Lussier2018b) whereas research on triarchic-based measures indicate that boldness is orthogonal to meanness and disinhibition. The term orthogonal means that boldness is not correlated with meanness or disinhibition (Gatner et al., Reference Gatner, Douglas and Hart2016; Lilienfeld et al., Reference Lilienfeld, Watts, Smith, Latzman and Patrick2018a; Patrick, Reference Patrick2018; Patrick et al., Reference Patrick, Fowles and Krueger2009). It remains unclear whether this result reflects the uniqueness of the triarchic model itself or limitations inherent to self-report methods of assessing psychopathy.
Whereas the self-report nature of the PPI-R is a potential weakness, a strength of this instrument is that it was developed using a bottom-up approach. By contrast, the PCL-R and Psychopathy Checklist: Youth Version (PCL:YV) were developed using a top-down approach, in which traits were selected based on Cleckley’s description of psychopathy and then validated based on the 20 items included. A bottom-up approach is where psychopathy traits are selected from a large list of possible traits. These traits are then included as items in a measurement tool. The measurement tool is further refined through statistical analysis, where items are culled or modified to improve reliability and validity (Livesley, Reference Livesley2007). A bottom-up approach tends to be more inclusive, thus reducing the likelihood that important traits were excluded from the measure. A bottom-up approach ensures that measures are data-driven and not only informed by clinical experience.
The Comprehensive Assessment of Psychopathic Personality
Unlike the triarchic model’s suggestion that psychopathy traits are adaptive, the CAPP model (Cooke et al., Reference Cooke, Hart, Logan and Michie2004) was developed under the assumption that psychopathy reflects maladaptive personality traits. To avoid overreliance on Cleckleyan descriptions, the CAPP was developed through a systematic review of the academic literature. Whereas the PCL-R includes just 20 items, the CAPP model includes 33 items, referred to as symptoms. A unique feature of the CAPP is that it was developed and refined through interviews with subject-matter experts (Cooke et al., Reference Cooke, Hart, Logan and Michie2004, Reference Cooke, Hart, Logan and Michie2012). The validation of the CAPP conceptual model included prototypicality analysis, in which subject-matter experts reviewed individual symptoms of psychopathy included in the CAPP and specified the extent to which each symptom was emblematic of psychopathy. Thus, like the triarchic model, the CAPP model can be considered a bottom-up approach. The CAPP developers believed that it was better to identify through statistical analysis whether certain symptoms should be excluded from the construct (Cooke et al., Reference Cooke, Hart, Logan and Michie2012). This meant that the developers favored including symptoms even if they potentially were not central to psychopathy. To this point, all 33 symptoms have been retained in the CAPP conceptual model.
The symptoms of psychopathy identified in the CAPP conceptual model are described using a lexical approach. A lexical approach assumes that the meaning of psychopathy is encoded in natural language. Contrary to Maruna’s assertion that psychopathy traits were “invented in the 1990s” (American Society of Criminology, 2024), the CAPP developers argued that since psychopathy traits have been observed for thousands of years, they should be describable using natural language rather than terms-of-art or scientific jargon (Cooke et al., Reference Cooke, Hart, Logan and Michie2012). This view of psychopathy aligns with Wittgenstein’s (Reference Wittgenstein1993) argument that definitions are crafted through the contexts in which they are used in everyday life.
The 33 symptoms identified by the CAPP developers (Cooke et al., Reference Cooke, Hart, Logan and Michie2004) were conceptually allocated into 6 domains. The Attachment domain reflects a failure to form caring, close, and stable emotional bonds with others. The Behavioural domain involves problems developing adaptive strategies to deal with life tasks in a systematic, consistent, planned manner; instead, behaviour is impulsive and disruptive. The Cognitive domain describes rigid thought patterns, negative attitudes toward others, and poor concentration and planning. The Dominance domain focuses on problems in relationships, including a manipulative, insincere, controlling, and garrulous interpersonal style. The Emotion domain depicts an inability to fully experience and regulate certain emotions and issues with the appropriateness of affective responses. The Self domain reflects an unrealistic, incomplete, and egocentric self-identity in which people have an inflated perception of social roles and relations with others.
The CAPP-Institutional Rating Scale (CAPP-IRS) formalizes the measurement of the CAPP conceptual model (Cooke et al., Reference Cooke, Hart, Logan and Michie2012). Like the PCL, the CAPP-IRS is an expert-rating tool in which a trained assessor conducts an interview and subsequently rates symptoms. Unlike the PCL-R and PCL:YV, the CAPP-IRS avoids giving attention to a person’s criminal history as part of the assessment of psychopathy. The CAPP-IRS developers thus prioritized the measurement of maladaptive personality traits associated with psychopathy. Even the Behavioural domain of the CAPP-IRS avoids requiring raters to assess criminal conduct to complete ratings. Consistent with this focus, the absence of behavioural anchors in the CAPP-IRS ensures that the assessment emphasizes personality traits. For example, raters do not need to confirm specific behavioural anchors (e.g., “shouting at an intimate partner”) to assess the severity of a symptom (e.g., “uncaring”).
My experience implementing the CAPP-IRS (e.g., Dawson et al., Reference Dawson, McCuish, Hart and Corrado2012; McCuish et al., Reference McCuish, Hanniball and Corrado2019) is that, as its name suggests, it is far more comprehensive than PCL-based measures of psychopathy. This benefit must be balanced against the longer administration time. I also feel that it took me longer to develop confidence in using the CAPP-IRS compared to the PCL:YV. This is not because the CAPP-IRS manual is less clear, nor do I believe that my training was insufficient. There is simply much more to consider when administering the CAPP-IRS. I certainly prefer both instruments to self-report measures. With incarcerated youth populations, I regularly witnessed participants struggling to understand interview questions. Semi-structured interviews allow for clarifying questions, something that is not possible with self-report survey measures.
Psychopathy Traits as Extreme Versions of Broader Personality
The CAPP defines psychopathy as a combination of maladaptive personality traits specific to psychopathy. A simpler perspective is that the personality traits that comprise psychopathy are not necessarily unique to psychopathy. Instead, the traits that comprise psychopathy reflect extreme versions of general personality traits. Describing psychopathy as an extreme expression of personality traits differs from perspectives that describe psychopathy as a personality disorder. Having a personality disorder implies some form of dysfunction or maladaptive consequence (e.g., involvement in criminal behaviour, negative social relationships). In contrast, having extreme personality traits does not necessarily imply dysfunction. For example, being extremely introverted is not necessarily maladaptive if steps are taken to be engaged socially when needed. Thus, the triarchic model views psychopathy as adaptive; the CAPP model views psychopathy as maladaptive; and the perspective that psychopathy merely reflects extreme versions of general personality is somewhat neutral on the matter. It is noteworthy that these three perspectives have such unique views despite all being influenced by Cleckley. This reiterates Wittgenstein’s (Reference Wittgenstein1993) point about the importance of being public rather than private about definitions. One could claim that inside their box is not a beetle but “Cleckleyan psychopathy.” However, failure to expand upon what “Cleckleyan psychopathy” means could result in assumptions of a shared understanding of psychopathy when, in reality, there are important differences.
There are several conceptual models that describe different dimensions of human personality. The five-factor model is especially prominent (see Miller, Reference Miller2012, for a review). This model is commonly referred to as the “Big Five.” The five-factor model specifies a hierarchical organization of personality traits from five domains: Extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience. The acronyms “CANOE” and “OCEAN” are helpful devices for remembering these five traits. Extraversion describes the tendency to be assertive and sociable rather than quiet and reserved. Agreeableness describes a preference for being cooperative rather than combative. Conscientiousness describes the ability to approach tasks systematically and without distraction. Neuroticism refers to unstable and negative emotions rather than emotional stability. Openness to experience refers to a sensitivity to others and a willingness to try new things (Miller, Reference Miller2012).
Widiger and Lynam (Reference Widiger, Lynam, Millon, Simonsen, Birket-Smith and Davis1998) outlined how psychopathy fits within the five-factor model. Again, it is the extreme expression of personality traits that relates to psychopathy. From the Extraversion factor, traits resembling psychopathy included an absence of warm and positive emotions. Another trait from the Extraversion factor, sensation-seeking, is present in extreme form for people with psychopathy traits. From the Agreeableness factor, traits relevant to psychopathy include the absence of modesty, care for others, and earnestness. From the Conscientiousness factor, a lack of discipline, goal-directed behaviour, and diligence are consistent with psychopathy. From the Neuroticism factor, traits include high levels of impulsivity and anger, along with a lack of depression. The fifth factor, Openness to Experience, was considered to lack any indicators of personality traits relevant to psychopathy (Lynam & Miller, Reference Lynam and Miller2015).
The Elemental Psychopathy Assessment (EPA; Lynam et al., Reference Lynam, Gaughan, Miller, Miller, Mullins-Sweatt and Widiger2011) was developed as a self-report questionnaire that reflects maladaptive versions of five-factor model traits. The EPA items measure interpersonal antagonism, emotional (in)stability, disinhibition, and narcissism dimensions of psychopathy. The EPA overlaps not just with the five-factor model but also with Cleckley’s description of interpersonal, affective, and behavioural domains of dysfunction (Patrick et al., Reference Patrick, Fowles and Krueger2009; Sellbom et al., Reference Sellbom, Bromberg, O’Donohue and Bromberg2019). To combat concerns about self-report measures, the EPA includes two validity scales. One scale tests for inattention to survey questions (e.g., “I try to eat something almost every day”). The other scale assesses social desirability bias. Social desirability bias reflects a person’s efforts to portray themselves in an overly positive light (e.g., “I have never in my life been angry at another person”). Like the CAPP conceptual model and the associated CAPP-IRS measure of psychopathy, the EPA favors an over-inclusive strategy by incorporating a broad range of personality traits to help identify and eliminate traits that are not central to psychopathy.
Chapter Summary
Although psychopathy is considered one of the most important concepts in forensic psychology and the criminal legal system (Monahan, Reference Monahan2006), the academic literature on psychopathy is relatively inaccessible to readers without prior background knowledge. This is unfortunate given the clear public interest in psychopathy research. This interest has been satiated by resources that are more easily accessible, including popular psychology books, TED Talks, and True Crime podcasts. Unfortunately, these resources tend to be wildly inaccurate and there is empirical evidence that they fail to advance the general public’s understanding of psychopathy (Keesler & DeMatteo, Reference Keesler and DeMatteo2017; Ostapchuk, Reference Ostapchuk2018). I wrote this chapter with the goal of building toward a shared understanding of the history of psychopathy as a disorder. There is not too much of a divide between Pinel’s concept of manie sans délire in the early nineteenth century and perspective on psychopathy in the twenty-first century. However, in the period between Pinel and contemporary research, there has been substantial variation in how psychopathy has been described. Some descriptions, especially in the early twentieth century, were influenced by positive attitudes toward the eugenics movement. Such descriptions were rightfully attacked by criminologists and sociologists (e.g., Sutherland, Reference Sutherland1949; Tennenbaum, Reference Tennenbaum1977). Although psychopathy research has evolved, the views of some criminologists have not necessarily been updated, leading to skepticism about the meaningfulness of psychopathy and the rigor of psychopathy research (American Society of Criminology, 2024; Maruna, Reference Maruna2025).
The DSM has contributed to confusion, not just among general audiences, but also among some subject-matter experts, about what psychopathy is and whether it is the same as antisocial personality disorder or sociopathy (Shipley & Arrigo, Reference Shipley and Arrigo2001). In short, the DSM has used both antisocial personality disorder and sociopathy as terms intended to represent psychopathy. The term sociopathic personality disturbance was replaced in later versions of the DSM by antisocial personality disorder. The study of sociopathy has all but disappeared from the research agendas of subject-matter experts. Antisocial personality disorder represents a simplified, watered-down version of psychopathy that emphasizes behavioural manifestations of the construct and overlooks key personality traits.
Hervey Cleckley, a pioneer of contemporary psychopathy research, identified interpersonal, affective, and behavioural domains of functioning as central to psychopathy. The PCL-R, sometimes referred to as the gold standard in the assessment of psychopathy (Boduszek & Debowska, Reference Boduszek and Debowska2016), is based on Cleckley’s description of psychopathy. Three other contemporary descriptions of psychopathy and their associated measurement tools include the triarchic model (and the PPI-R), the CAPP conceptual model (and the CAPP-IRS), and the view of psychopathy as an extreme manifestation of general personality traits (and the EPA). There is considerable overlap between these descriptions, especially in terms of the identification of interpersonal and affective traits as central features of psychopathy. However, as discussed in the next chapter, this overlap has not prevented plenty of debate within the academic literature on the nature of psychopathy.
