Robert Hare’s Psychopathy Checklist-Revised (PCL-R) and the briefer screening version (PCL:SV) are the predominant tools for assessing psychopathic traits in adult forensic and correctional settings. Psychopathy is a multidimensional personality disorder characterized by an arrogant and manipulative interpersonal style, poverty in major affective reactions, an impulsive and irresponsible lifestyle, and persistent and inadequately motivated antisocial behavior. Contemporary conceptualizations of psychopathy derive from Hervey Cleckley’s seminal work in the 1940s in which he provided comprehensive descriptions of institutionalized psychiatric case studies. Cleckley defined psychopathy primarily in terms of interpersonal and affective deficits under a surface of outwardly normal behavior, which he termed a mask of sanity. Considerable research has demonstrated that adults presenting with psychopathic traits embark on a chronic, proactively (i.e., without provocation, for instrumental gain) aggressive, violent, and criminal lifestyle, and as such are highly overrepresented in the criminal justice system.
The PCL and its derivatives are often used by clinicians and forensic professionals for violence risk assessment, although not originally intended for this purpose. In fact, in his case descriptions, Cleckley did not characterize psychopaths as explosively violent, predatory, or cruel; rather, he suggested that the harm that they caused was secondary to their shallow affect. Modern perception of psychopathy’s association with criminal antisocial behavior stems from William and Joan McCord’s work with incarcerated offenders, rather than psychiatric patients. Many current measures of psychopathy assess law-breaking behaviors in addition to the core affective and interpersonal features, which some scholars view as tangential to the construct, constituting a matter of contention. This is due in part to the fact that most existing measures of psychopathy are based on the PCL, which weighs antisocial and criminal externalizing features as strongly as the traits of emotional detachment and interpersonal exploitation. Research finds that the predictive utility of PCL assessments is largely derived from its assessment of antisocial and disinhibitory tendencies rather than interpersonal and affective features.
Psychometric Properties and Factor Structure
Hare’s initial efforts toward developing this clinical diagnostic instrument consisted of a global ratings system that was based on Cleckley’s institutional description, in which a diagnostic rating from 1 to 7 was assigned to indicate an individual’s likeness to a prototypical psychopath (1 = clearly nonpsychopathic, 7 = definitely psychopathic). However, this original rating system required considerable experience and knowledge of Cleckley’s conceptualization and was not easy to disseminate to other researchers or clinicians. Hare’s original checklist consisted of 22 items that were chosen from a larger item pool on the basis of how effectively they discriminated, as a set, between high and low scores on the global ratings system. Individuals’ likeness to a prototypical psychopath was rated on a 3-point scale (0 = item does not apply; 1 = item applies somewhat; 2 = item definitely applies). The subsequent revised version (PCL-R) dropped two items (“previous diagnosis of psychopathy or similar” and “antisocial behavior not due to alcohol intoxication”) from the original checklist with poor factor loadings and included clarified scoring criteria for ease of use for evaluators.
PCL assessments are to be conducted by trained professionals with semi-standardized administration procedures. The PCL-R involves a 60- to 90-minute semi-structured clinical interview supplemented with an extensive case history institutional file review, providing a fairly objective assessment of adult psychopathy. The individual is rated on 20 psychopathic traits that define psychopathy across two dimensions: an interpersonal–affective dimension (Factor 1; divisible into affective and interpersonal facets) and a lifestyle– behavioral dimension (Factor 2; divisible into impulsive– irresponsible lifestyle and antisocial behavior facets). PCL manuals provide a description of each item and information to be used in decision- making when rating an individual. The standard interview covers a range of topics including education, employment history, family and home life background, relationships and children, drug and alcohol use, and criminal history. Item ratings are summed to yield a global score representing the degree to which the individual embodies the prototypical psychopath with a maximum score of 40. Individuals scoring equal or greater than 30 have traditionally been designated as psychopathic and at high risk of violent, antisocial behavior.
The PCL:SV was developed as a briefer version of the PCL-R to screen for psychopathy and to determine whether more comprehensive assessment is warranted. This abbreviated version includes 12 items that are thought to be representative of Factor 1 and Factor 2 from the PCL-R (labeled Part 1 and Part 2) and has been used with civil psychiatric patients, community samples, and in personnel selection. Items removed include pathological lying, shallow affect, need for stimulation, parasitic lifestyle, promiscuous sexual behavior, many short marital relationships, early behavior problems, and criminal versatility. PCL:SV scores correlate strongly with the PCL-R (weighted r ~ 0.80). Similar to the PCL-R, each item is rated on a 3-point Likert-type scale by trained professionals based on a clinical interview and file review. While factor analyses were not completed in the original development of the PCL:SV, some factor analytic studies conducted since support the same two-factor structure as the PCL-R. Others have found support for a three-factor model across PCL measures tapping moderately correlated (r ~ 0.50) but separable affective (e.g., callousness/lack of empathy), interpersonal (e.g., glibness and superficial charm), and antisocial–behavioral deviance (e.g., chronic impulsive and irresponsive behavior, life-span antisocial behavior) dimensions.
Convergent and Discriminant Validity
PCL scores correlate more strongly with the McCord’s definition of criminal psychopathy rather than Cleckley’s masked disturbance of attenuated affect. High PCL-R and PCL:SV scores are positively associated with measures of impulsivity, aggression, and criminal behavior (i.e., convergent validity—measures that should be related are related) and inversely associated with measures of empathy and affiliation (i.e., discriminant validity—measures that should not be related are not related). Specifically, research indicates that high scores on the interpersonal–affective dimension are associated with narcissism, social dominance and potency, and low empathy and negatively related to measures of negative emotionality (i.e., anxiety and depression). Those scoring high on the interpersonal–affective dimension also show reduced fear-potentiated startle in the presence of threat. Conversely, the lifestyle– behavioral factor is associated with alienation and externalizing maladaptive characteristics and behaviors, such as aggression, impulsivity, sensation seeking, drug and alcohol use, and criminal behavior.
Predictive Validity
PCL measures were not developed for the explicit purpose of risk assessment, for which many validated tools are available; however, they show clinical utility for predicting nonviolent and violent criminal recidivisms. As a consequence, they have increasingly been used in a variety of legal contexts, both criminal and civil, to assist risk assessment in cases regarding commitment pursuant to sexual predator laws, civil commitment, parole determinations, institutional placement, death penalty sentencing, and sentence enhancement/ mitigation. Surveys of U.S. forensic practitioners suggest that the PCL-R, specifically, is among the most commonly used clinical instruments for assessing recidivism risk.
Meta-analytic studies examining whether PCL measures can predict recidivism consistently reveal a small to moderate association between PCL total scores and future offending, including institutional behavior problems and general and violent recidivism. This finding is observed among male and female offenders, juvenile offenders, forensic psychiatric inpatients, community samples, and European samples. Research examining the PCL’s predictive validity has predominantly been conducted with White North American male samples; however, recent efforts have attempted to validate its use with other ethnicities, but further research is needed to determine the reliability of the measure with these samples. The predictive validity of PCL scores is generally stronger when longer follow-up intervals are used. The PCL does exhibit adequate predictive validity for general and violent recidivism among sexual offenders but is less useful in the prediction of sexual reoffending specifically. Thus, it is clear that the PCL measures demonstrate at least some degree of predictive validity with regard to future antisocial behavior.
As mentioned earlier, most of the PCL’s predictive utility is attributable to its assessment of antisocial deviance features of psychopathy rather than interpersonal traits reflecting emotional detachment. Several meta-analyses consistently demonstrate that the lifestyle and antisocial– behavioral features of the PCL, which assesses general externalizing psychopathology that is not specific to psychopathy, more strongly predict future antisocial conduct than the interpersonal and affective features. The relative superiority of the lifestyle–behavioral deviance dimension for predicting antisocial behavior holds true across various outcome measures, including institutional misconduct and general and violent recidivism. These findings challenge the assumption that the measures’ association with violence is an indication that emotionally detached psychopaths use violence to prey upon others. However, some research has demonstrated that Factor 1 is more strongly associated with instrumental aggression relative to Factor 2 that is more strongly associated with reactive aggression. The PCL measures may tap trait aggression, externalizing features, or a chronic and versatile history of antisocial behavior that predicts future violence but are not specific to psychopathy. It has been further suggested that psychopathy dimensions may have an additive or interactive effect such that the prediction of recidivism or violence is substantially enhanced when they are considered together, although findings are inconsistent.
Recommendations for Use
The popularity of PCL measures in forensic risk assessment appears to transcend tools developed specifically for the purpose of evaluating risk of future offending; however, some important considerations are worth mentioning. First, Hare recommended that PCL measures are not appropriate for use as a stand-alone risk assessment tool. Rather, PCL measures may be best utilized as a complement to other risk assessment tools that have been designed to predict specific outcomes. Second, while both the PCL-R and the PCL:SV have recommended cutoff scores (>30 and >18, respectively) constituting a psychopathy diagnosis, this is founded on little research support. There is still surmountable debate in the field on an accurate psychopathy definition; however, researchers support that psychopathic traits are continuous (i.e., dimensional) rather than taxonic (i.e., categorical). Third, in the tool’s development, Hare excluded Cleckley’s positive adjustment indicators regarding these items as irrelevant to the psychopathy construct. Other researchers have disagreed with this exclusion, suggesting that characteristics of fearlessness and stress immunity are essential elements of psychopathy. Cleckley described individuals with such paradoxical positive adjustment and maladaptive features, a combination of traits often observed among individuals in certain professions, such as, politicians or investment bankers—a subgroup some in the field have termed successful psychopaths. In contrast, some individuals designated as psychopathic according to the PCL and its derivatives present with high anxiety levels or other emotional maladjustment and are typically described as secondary psychopathy variants in the literature.
Although phenotypically indistinguishable from primary psychopathy variants with regard to both Factor 1 and Factor 2 traits, experiences of social and environmental adversity (i.e., childhood trauma or maltreatment) are instead central to theories of secondary psychopathy. Several studies have also found that secondary psychopathy variants show a more reactively aggressive and violent profile than primary variants. Since “an absence of anxiety or other ‘neurotic’ symptoms” was dropped as an indicator between Cleckley’s psychopathy criteria and PCL assessments, some researchers include measures of negative emotionality (i.e., anxiety) to distinguish secondary psychopathy variants.
Finally, several researchers and clinicians believe that psychopathic individuals are resistant to treatment, and consequently, PCL assessments have been used to exclude those scoring in the psychopathic range from receiving treatment. However, accumulating research by Stephen Wong and colleagues finds that psychopathic offenders receiving comprehensive and intensive intervention focused on targeting criminogenic behaviors and individual interpersonal personality features, in line with the Risk-Need-Responsivity principles, commit less serious offenses than matched controls receiving standard correctional programs. Also, in light of the aforementioned research supporting heterogeneity among those with psychopathic traits, a one-size-fits-all approach to intervention may not be capturing the unique treatment needs of psychopathy variants that show distinct correlates and putative etiological factors.
In conclusion, there is still disagreement in the field as to how best to operationalize the prototypical psychopath. However, with the development of the well-validated PCL assessment and its derivatives, including a youth version, scientific research on psychopathic traits is abundant. The PCL was not designed to be used as a risk assessment tool; however, it is commonly used in judicial settings to identify those individuals at greatest risk of persistent, violent, antisocial behavior. In the United States, specifically, the use of PCL measures in the courtroom is increasingly introduced by prosecution in capital punishment cases and as a determinant in treatment allocation. Yet, research has found that adult psychiatric patients scoring high on the PCL-R and receiving targeted, intensive intervention were less likely to behave violently and committed less serious offenses than those who attended fewer treatment sessions or received standard treatment. Continued research efforts to elucidate how the various dimensions of psychopathy, alone and in combination with anxiety measures, designate a subgroup of antisocial individuals at greatest risk of persistent violence and lawbreaking behavior hold promise toward informing theory and practice.
References:
- Cleckley, H. (1941). The mask of sanity (5th ed.). St. Louis, MO: Mosby.
- Hare, R. D. (2003). The Hare Psychopathy Checklist– Revised (2nd ed.). Toronto, Canada: Multi-Health Systems.
- Hart, S. D., Cox, D. N., & Hare, R. D (1995). The Hare Psychopathy Checklist: Screening Version (1st ed.). Toronto, Canada: Multi-Health Systems.
- Karpman, B. (1948). Conscience in the psychopath; another version. American Journal of Orthopsychiatry, 18(3), 455–491. Retrieved from https://doi.org/10.1111/j.1939-0025.1948.tb05109.x
- McCord, W., & McCord, J. (1964). The psychopath: An essay on the criminal mind. Oxford, UK: Van Nostrand.
- Patrick, C. J. (Ed.). (2005). Handbook of psychopathy. New York, NY: Guilford Press.
- Walters, G. D. (2003). Predicting institutional adjustment and recidivism with the psychopathy checklist factor scores: A meta-analysis. Law & Human Behavior, 27(5), 541–558.
- Wong, S. C., Gordon, A., Gu, D., Lewis, K., & Olver, E. (2012). The effectiveness of violence reduction treatment for psychopathic offenders: Empirical evidence and a treatment model. International Journal of Forensic Mental Health, 11(4), 336–349. Retrieved from https://doi.org/10.1080/14999013.2012.746760