Hare Psychopathy Checklist – Revised (PCL-R)

1. Abstract

The Hare Psychopathy Checklist – Revised (PCL-R) is widely recognized as the international gold standard for the clinical, legal, and forensic operationalization and diagnostic assessment of psychopathy. Conceptualized and refined by Canadian psychologist Robert D. Hare across several decades of empirical psychometric investigation, the PCL-R evaluates the presence and severity of interpersonal, affective, lifestyle, and antisocial behavioral characteristics. Comprising 20 complex symptom-construct items, the instrument uses a three-point ordinal rating scale (0 = item does not apply; 1 = item applies somewhat; 2 = applies definitely), yielding a dimensional dimensional score ranging from 0 to 40. In standard North American forensic and correctional contexts, a diagnostic threshold score of 30 or greater denotes the clinical designation of psychopathy, whereas European jurisdictions frequently employ a diagnostic cutoff score between 25 and 26 to adjust for cross-cultural scoring base rates.

Rather than relying on self-report questionnaires, which are vulnerable to deceptive distortion, impression management, and lack of insight, the administration of the PCL-R integrates a rigorous, semi-structured clinical interview of roughly 90 to 120 minutes with a comprehensive collateral review of institutional, correctional, psychiatric, educational, and legal records. Psychometrically, the instrument exhibits high internal consistency (Cronbach’s alpha values typically ranging between .85 and .90, with benchmark normative indices at .87), exceptional inter-rater reliability (intraclass correlation coefficients frequently exceeding .90, benchmarked at .94), and robust test-retest reliability (.89). Structural analyses have validated both a foundational two-factor framework (Interpersonal/Affective vs. Social Deviance/Antisocial Lifestyle) and a contemporary four-facet hierarchical model (Facet 1: Interpersonal; Facet 2: Affective; Facet 3: Lifestyle; Facet 4: Antisocial). Clinically, the PCL-R demonstrates unparalleled predictive validity in forecasting general and violent criminal recidivism, institutional misconduct, and therapeutic response, cementing its role in forensic risk assessment, criminal jurisprudence, and clinical neuropsychology.

2. Keywords

PCL-R, Psychopathy Checklist-Revised, Robert Hare, psychopathy assessment, forensic psychometrics, antisocial personality, violent recidivism, risk assessment, interpersonal affect, callous-unemotional traits, criminal versatility, factor structure.

3. Authors

The Hare Psychopathy Checklist – Revised was developed by Robert D. Hare, Ph.D., Professor Emeritus of Psychology at the University of British Columbia (Vancouver, Canada). Dr. Hare is an internationally recognized pioneer in the psychophysiological, neurobiological, and psychometric study of psychopathic personalities. For more than four decades, his research laboratory examined autonomic underpinnings, affective processing abnormalities, language lateralization disruptions, and behavioral manifestations of psychopathy within penitentiary and clinical populations. Dr. Hare also collaborated with international forensic researchers, including Dr. David J. Cooke, Dr. Michiel de Vries Robbé, Dr. Mikael Grann, and Dr. Adelle Forth, to refine the psychometric measurement of psychopathy across developmental stages, resulting in derivative tools such as the Psychopathy Checklist: Screening Version (PCL:SV) and the Psychopathy Checklist: Youth Version (PCL:YV).

4. Purpose

The primary purpose of the Hare Psychopathy Checklist – Revised is to provide an objective, reliable, and standardized dimensional rating of psychopathic and severe antisocial personality traits in adult clinical, legal, and correctional populations. Prior to the formal introduction of the original Psychopathy Checklist in 1980 and its revised edition in 1991 (with updated normative data in 2003), clinical determinations of psychopathy suffered from marked diagnostic unreliability, idiosyncrasy, and over-reliance on subjective clinical impressions. The PCL-R emerged as a systematic psychometric response to this chaos, bridging the gap between descriptive psychiatric typologies and quantitative diagnostic measurement.

In legal and forensic environments, the PCL-R serves several critical applications:

• Violence and Recidivism Risk Assessment: Assessing an offender’s risk of committing future violent and non-violent crimes upon release, during conditional release, or while under parole consideration.
• Correctional Classification and Institutional Management: Assisting prison administrators in classifying inmates based on their risk of escape, predatory aggression, intimidation of peers, and manipulation of correctional staff.
• Sentencing and Judicial Determinations: Serving as forensic expert evidence during capital sentencing proceedings, dangerous offender hearings, sexually violent predator (SVP) civil commitment evaluations, and transfer hearings from juvenile to adult courts.
• Treatment Planning and Prognostication: Evaluating treatment amenability. Individuals who score high on the PCL-R show high rates of attrition, minimal intrinsic motivation for prosocial change, and a tendency to manipulate group therapy dynamics, often requiring specialized management protocols rather than insight-oriented psychotherapy.
• Etiological and Neuroscientific Research: Serving as a standard criterion measure in neuroimaging (fMRI, structural MRI), electrophysiological (event-related potentials), neuroendocrinological, and behavioral genetics research into the neural bases of empathy, moral judgment, emotion processing, and executive dysfunction.

The theoretical rationale behind the PCL-R asserts that psychopathy is a multifaceted personality disorder characterized by a distinct constellation of interpersonal manipulation, affective deficits, chronic impulsivity, and persistent antisocial behavior. Because individuals with psychopathy are prone to pathologically lying, charming evaluators, and minimizing their antisocial histories, self-report measures alone are insufficient for forensic diagnosis. The PCL-R overcomes these reporting biases by mandating collateral record verification, ensuring that diagnostic scoring is anchored to verified historical conduct.

5. Psychological Construct

The psychological construct evaluated by the PCL-R reflects the psychopathic syndrome as delineated in modern psychopathology. Psychopathy is conceptualized not as a single discrete behavioral anomaly, but as a hierarchical, multi-dimensional syndrome encompassing severe interpersonal, affective, behavioral, and antisocial pathology. While the historical two-factor model divides the instrument into Interpersonal/Affective (Factor 1) and Social Deviance/Lifestyle (Factor 2) components, empirical research and the 2003 PCL-R manual update confirm a four-facet hierarchical structure that captures the disorder’s primary phenotypic manifestations:

Facet 1: Interpersonal

The interpersonal dimension captures the deceptive, dominant, and superficially polished social presentation characteristic of the psychopath. Specific manifestations include:

• Glibness / Superficial Charm (Item 1): A conversational style that is smooth, articulate, charming, and uninhibited, yet transparently insincere upon deeper analysis. The individual frequently tells plausible but fabricated stories to project confidence, often captivating audiences with exaggerated charismatic ease.
• Grandiose Sense of Self-Worth (Item 2): An inflated view of one’s abilities, intelligence, status, and self-importance. Individuals may express contempt for institutional authority, boast of unrealistic future triumphs, and view themselves as inherently superior to others.
• Pathological Lying (Item 4): Pervasive, habitual fabrication that occurs even when there is no apparent external reward or tactical advantage. When confronted with contradictions, the individual effortlessly fabricates new rationalizations without displaying shame or embarrassment.
• Conning / Manipulative (Item 5): The deliberate exploitation, deception, and psychological manipulation of family, associates, peers, and institutional staff for personal gain, amusement, or instrumental goals, accompanied by cold indifference to the victim’s distress.

Facet 2: Affective

The affective dimension reflects a marked blunting of emotional experience, moral awareness, and interpersonal empathy:

• Lack of Remorse or Guilt (Item 6): A striking absence of concern for the physical, emotional, or financial harm inflicted on victims. The individual may justify their actions by blaming victims, depicting them as deserving of exploitation.
• Shallow Affect (Item 7): Emotional poverty characterized by superficial, transient, and short-lived feelings. While the individual may display dramatic histrionic outbursts of anger or excitement, these displays lack genuine depth and subside quickly.
• Callous / Lack of Empathy (Item 8): A fundamental incapacity to experience empathy or compassion. The individual approaches others with cold, objective detachment, viewing people as instruments or obstacles.
• Failure to Accept Responsibility for Own Actions (Item 16): Persistent denial, rationalization, and externalization of blame for antisocial, unethical, or illegal conduct, often presenting themselves as the victim of systemic bias or judicial corruption.

Facet 3: Lifestyle

The lifestyle dimension captures chronic instability, sensation-seeking, and a lack of constructive long-term direction:

• Need for Stimulation / Proneness to Boredom (Item 3): A chronic intolerance for routine, accompanied by a restless drive for high-risk stimulation, novel thrills, and reckless activities.
• Parasitic Lifestyle (Item 9): Deliberate financial dependency on family, partners, or social safety nets, maintained through coercion, manipulation, or exploitation, alongside a refusal to engage in regular gainful employment.
• Lack of Realistic, Long-Term Goals (Item 13): An inability or unwillingness to formulate and pursue feasible long-term educational, occupational, or personal plans, often combined with grandiose, unfeasible ambitions.
• Impulsivity (Item 14): Actions executed spontaneously on the spur of the moment without forethought, consideration of consequences, or regard for personal or public safety.
• Irresponsibility (Item 15): Habitual failure to fulfill professional, contractual, financial, or personal obligations, such as defaulting on debts, neglecting dependents, and abandoning employment.

Facet 4: Antisocial

The antisocial dimension assesses early-onset, pervasive, and persistent violations of social norms and criminal codes:

• Poor Behavioral Controls (Item 10): Hypersensitivity to perceived slights, short-temperedness, and violent retaliatory behavior that erupts quickly and subsides with little residual remorse.
• Early Behavior Problems (Item 12): Serious behavioral infractions occurring prior to age 12, including chronic theft, persistent lying, vandalism, fire-setting, bullying, and severe truancy.
• Juvenile Delinquency (Item 18): Documented criminal conduct, arrests, or convictions occurring between the ages of 13 and 17.
• Revocation of Conditional Release (Item 19): Failure on parole, probation, bail, or conditional discharge due to technical violations, flight from custody, or the commission of new offenses.
• Criminal Versatility (Item 20): A documented legal history spanning numerous distinct categories of criminal offending (e.g., theft, assault, drug offenses, fraud, weapons violations), reflecting a broad disregard for the law rather than specialization in a single criminal enterprise.

Two additional items—Item 11: Promiscuous Sexual Behavior and Item 17: Many Short-Term Marital Relationships—load onto the total psychopathy score, reflecting unstable interpersonal and sexual dynamics, but are excluded from the four-facet structure due to cross-loadings and unique item variances.

6. Theoretical Framework

The theoretical foundations of the PCL-R rest on early descriptive psychopathology, later unified with evolutionary psychology, psychophysiology, and cognitive neuroscience. The direct clinical precursor to Hare’s psychometric operationalization is Hervey M. Cleckley’s landmark 1941 treatise, The Mask of Sanity. Cleckley described psychopathy as an insidious clinical paradox: an individual who displays an outward appearance (“mask”) of intellectual normality and psychological health, yet harbors a profound underlying deficit in affective processing, moral conscience, and self-regulation. Cleckley outlined 16 primary diagnostic criteria, emphasizing that psychopaths lack the emotional depth required to form genuine human attachments, feel shame, or learn from punishment.

Robert Hare expanded upon Cleckley’s descriptive framework by recognizing that Cleckley underemphasized the overt antisocial, criminal, and predatory features observed in forensic settings. While Cleckley viewed criminality as secondary or incidental to the core personality defect, empirical correctional data demonstrated that overt behavioral deviance was a defining feature of the disorder. Hare’s framework integrated Cleckley’s interpersonal-affective features with the lifestyle and criminal deviance commonly observed in prison populations, operationalizing the syndrome into a standardized rating methodology.

Contemporary psychobiological theories provide significant empirical support for the construct measured by the PCL-R:

• The Low Autonomic Arousal / Fearlessness Hypothesis: Originating from the work of David Lykken (1957) and validated across decades of psychophysiological testing, this model posits that individuals high in Factor 1 psychopathy possess an innate deficit in fearful arousal and behavioral inhibition. Consequently, they show muted electrodermal and cardiac reactivity to conditioned aversive stimuli, impairing passive avoidance learning and moral socialization.
• The Paralimbic System Dysfunction Model: Modern neuroimaging research, led by Kent Kiehl and colleagues, indicates that the core features of the PCL-R are linked to functional and structural abnormalities within a unified paralimbic circuit. This circuit includes the amygdala, orbitofrontal cortex (OFC), insular cortex, anterior cingulate cortex (ACC), and superior temporal gyrus. Structural reductions in gray matter volume and disrupted white-matter connectivity (such as within the uncinate fasciculus) impair the integration of emotional cues with cognitive decision-making.
• The Response Modulation Hypothesis: Developed by Joseph Newman and colleagues, this cognitive-attentional model asserts that psychopathy involves a fundamental deficit in processing secondary peripheral information when engaged in goal-directed behavior. Once focused on a reward, individuals with high PCL-R scores fail to allocate attentional resources to peripheral cues signaling punishment, social feedback, or collateral harm, leading directly to impulsive and irresponsible actions.

7. Validity

The PCL-R possesses an extensive empirical literature supporting its construct, convergent, discriminant, and predictive validity across diverse clinical and forensic settings.

Construct and Structural Validity

Construct validity is evidenced by the checklist’s ability to delineate a distinct clinical entity separated from Axis I psychiatric conditions (e.g., schizophrenia, major affective disorders) and general Antisocial Personality Disorder (ASPD) as codified in the DSM-5. While roughly 50% to 80% of adult male prison inmates meet the DSM-5 criteria for ASPD, typically only 15% to 25% score at or above the PCL-R diagnostic cutoff score of 30. The PCL-R thereby avoids criterion contamination by demanding evidence of both core interpersonal/affective pathology and behavioral deviance, successfully identifying the most severe and recalcitrant subgroup within broader antisocial populations.

Convergent and Discriminant Validity

Convergent validity is robust, showing strong positive correlations with alternative clinician ratings, observational protocols, and self-report measures of psychopathic personality traits, including the Psychopathic Personality Inventory-Revised (PPI-R; Lilienfeld & Andrews, 1996), the Levenson Self-Report Psychopathy Scale (LSRP), and the Triarchic Psychopathy Measure (TriPM). Factor 1 (Interpersonal/Affective) correlates significantly with self-reported narcissism, Machiavellianism, coldheartedness, and low trait anxiety, while Factor 2 (Social Deviance) correlates with trait impulsivity, substance use disorders, and early childhood conduct disorder.

Discriminant validity is supported by minimal or non-significant correlations with major neuroses, internalized affective distress, and intelligence. Psychopathy as assessed by the PCL-R operates orthogonally to general cognitive ability (full-scale IQ), confirming that the manipulative, superficial charm observed in psychopaths does not require superior intellect.

Predictive Validity

The predictive validity of the PCL-R regarding antisocial recidivism and violent conduct inside and outside institutional settings is extensively documented:

• Violent and General Recidivism: Extensive meta-analyses (e.g., Hemphill, Hare, & Wong, 1998; Leistico et al., 2008) indicate that PCL-R total and Factor 2 scores yield consistent Cohen’s d effect sizes ranging from .55 to .80, and Area Under the Curve (AUC) receiver operating characteristic indices typically between .70 and .80. These values confirm its standing as one of the most powerful individual predictors of future violent re-offending.
• Institutional Infractions: In correctional and forensic psychiatric facilities, high PCL-R scores reliably predict verbal intimidation, predatory physical assaults against staff and inmates, escape attempts, and substance smuggling.
• Treatment Resistance: High PCL-R scores predict elevated rates of premature attrition from therapeutic programs, resistance to behavioral modification, and disruptive behavior in therapeutic communities.

8. Reliability

The PCL-R demonstrates high reliability coefficients across international settings, provided that examiners meet professional qualification standards and adhere strictly to standard administrative procedures.

Internal Consistency

Normative validation cohorts encompassing thousands of male and female offenders across North America, the United Kingdom, and Scandinavia demonstrate high internal consistency for the total scale:

• PCL-R Total Score: Benchmark Cronbach’s alpha ($lpha$) coefficients consistently range between .85 and .90 (mean $lpha = .87$).
• Factor 1 (Interpersonal/Affective): Alpha coefficients typically range between .80 and .86.
• Factor 2 (Social Deviance): Alpha coefficients typically range between .82 and .88.
• Four Facets: Coefficients for individual facets vary based on their shorter item lengths: Facet 1 (Interpersonal) $lpha pprox .78 ext{–}.83$; Facet 2 (Affective) $lpha pprox .75 ext{–}.81$; Facet 3 (Lifestyle) $lpha pprox .72 ext{–}.79$; and Facet 4 (Antisocial) $lpha pprox .74 ext{–}.82$.

Inter-Rater Reliability

Because the PCL-R is an examiner-rated instrument requiring clinical judgment, inter-rater reliability is a crucial psychometric metric. Extensive multi-site studies have demonstrated high inter-rater agreement when evaluations are conducted by trained assessors:

• Single-Rater Intraclass Correlation Coefficients ($ICC_1$): Typically range between .86 and .90.
• Averaged-Rater Intraclass Correlation Coefficients ($ICC_2$): Benchmark studies (e.g., Hare et al., 2000) demonstrate $ICC_2$ values reaching .94 for the total score.
• Field Reliability Considerations: While controlled research protocols consistently yield $ICC$s exceeding .90, field studies of routine legal practice highlight the risk of “adversarial allegiance”—a phenomenon where prosecution-retained experts often produce systematically higher scores than defense-retained experts. This underscores the need for continuous quality control and calibration training.

Test-Retest Reliability

The temporal stability of the PCL-R reflects its underlying construct as an enduring personality configuration. Test-retest reliability across multi-year intervals yields correlation coefficients ranging from .85 to .91 (benchmark $r = .89$), demonstrating that psychopathic traits remain stable over time in adult populations.

9. Factor Analysis

The internal latent structure of the PCL-R has been extensively investigated using Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Item Response Theory (IRT).

The Classic Two-Factor Model

Robert Hare’s 1991 standard model posits a correlated two-factor solution derived from principal components and exploratory factor analyses:

• Factor 1: Interpersonal/Affective: Composed of 8 items (1, 2, 4, 5, 6, 7, 8, 16). Item loadings on Factor 1 typically range from .45 to .75. This factor represents the core emotional, affective, and interpersonal features of psychopathy.
• Factor 2: Social Deviance / Antisocial Lifestyle: Composed of 10 items (3, 9, 10, 12, 13, 14, 15, 18, 19, 20). Item loadings typically range from .50 to .80. This factor reflects behavioral instability, impulsivity, and chronic antisocial conduct.
• Unassigned Items: Item 11 (Promiscuous Sexual Behavior) and Item 17 (Many Short-Term Marital Relationships) do not load cleanly on either factor due to low item-to-total correlations and complex cross-loadings, but remain on the instrument to preserve total score validity.

The Hierarchical Four-Facet Model

Cooke and Michie (2001) proposed a three-factor, 13-item hierarchical model that removed antisocial items, arguing that criminal behavior is a consequence rather than a core component of the disorder. In response, Hare and colleagues (Hare, 2003; Neumann et al., 2007) conducted large-scale confirmatory factor analyses on thousands of forensic participants, establishing the validity of the four-facet hierarchical model:

Structural equation modeling across diverse demographic cohorts demonstrates good fit indices for this four-facet hierarchical model: Comparative Fit Index ($CFI$) > .94, Tucker-Lewis Index ($TLI$) > .93, and Root Mean Square Error of Approximation ($RMSEA$) < .055. Item Response Theory analyses confirm that Facet 2 (Affective) and Facet 1 (Interpersonal) items provide the greatest psychometric information at higher levels of the latent trait ($ heta$), while Facet 4 items assist in discriminating between moderate and elevated severity across correctional cohorts.

10. Instrument / Measurement Tool

• Test Type: Clinician-completed symptom construct rating scale, combining a semi-structured behavioral interview with independent collateral review of institutional, correctional, psychiatric, and police files.
• Format: Diagnostic rating checklist administered exclusively by qualified mental health professionals. Cannot be administered as a self-report instrument.
• Item Count: 20 items.
• Response Scale: 3-point ordinal rating format for each item:
  • 0 = Item does not apply (trait/behavior is absent; opposite disposition is present).
  • 1 = Item applies somewhat (uncertainty exists; trait is present to a mild or inconsistent degree).
  • 2 = Item applies definitely (trait is clearly present; behavior matches the operational definitions in the manual).
• Administration Time: Approximately 2 to 3 hours total (including 90–120 minutes for the clinical interview, alongside several hours dedicated to reviewing collateral records).
• Scoring and Factor Allocation:
  • Total Score Range: 0 to 40 points.
  • Diagnostic Cutoff Thresholds: A score of 30 or higher establishes a diagnosis of psychopathy in North American correctional populations. A threshold score between 25 and 26 is commonly used in European jurisdictions (such as the UK, Sweden, and the Netherlands) to account for cross-cultural scoring base rates. Non-criminal community samples typically score around 5 points, whereas the mean score across non-psychopathic criminal cohorts is approximately 22 points.
  • Factor 1 (Interpersonal/Affective): Items 1, 2, 4, 5, 6, 7, 8, 16.
    • Facet 1 (Interpersonal): Items 1, 2, 4, 5.
    • Facet 2 (Affective): Items 6, 7, 8, 16.
  • Factor 2 (Social Deviance/Antisocial Lifestyle): Items 3, 9, 10, 12, 13, 14, 15, 18, 19, 20.
    • Facet 3 (Lifestyle): Items 3, 9, 13, 14, 15.
    • Facet 4 (Antisocial): Items 10, 12, 18, 19, 20.
  • Non-Factor Items: Items 11 (Promiscuous sexual behavior) and 17 (Many short-term marital relationships) contribute directly to the total score, but are excluded from the two-factor and four-facet structural indices.
  • Missing Information Rules: Up to 5 items may be omitted if collateral records or interview responses are insufficient, with standardized mathematical prorating formulas provided in the manual. If more than 5 items are missing, the assessment is psychometrically invalid.

11. Permissions & Fee and Test Year

The original Psychopathy Checklist was published in 1980, followed by the formal publication of the Hare Psychopathy Checklist – Revised (PCL-R) manual in 1991, with an expanded 2nd Edition manual and normative update released in 2003. The PCL-R is a copyrighted psychometric instrument published and distributed commercially by Multi-Health Systems Inc. (MHS Assessments, Toronto, Canada).

The complete evaluation kit, including the technical rating manual, interview guide, and scoring sheets, is commercially available to qualified purchasers at a cost of approximately $550 to$650 USD. The PCL-R requires User Qualification Level C, the highest tier of assessment restriction. Purchasers must possess an advanced doctoral degree in psychology, psychiatry, or medicine, hold an active license with a relevant professional regulatory body, and demonstrate documented training in psychometric testing, clinical interviewing, and forensic assessment.

Because assigning a diagnosis of psychopathy carries significant legal and personal consequences—such as prolonged incarceration, high security classification, denial of parole, or civil commitment—examiners must complete formal, specialized PCL-R workshop training to ensure high inter-rater reliability and ethical application.

12. References

• Cleckley, H. M. (1941). The mask of sanity: An attempt to clarify some issues about the so-called psychopathic personality. C. V. Mosby Co.
• Cooke, D. J., & Michie, C. (2001). Refining the construct of psychopathy: Towards a hierarchical model. Psychological Assessment, 13(2), 171–188. https://doi.org/10.1037/1040-3590.13.2.171
• Freedman, M. D. (2001). False prediction of future dangerousness: Error rates and Psychopathy Checklist-Revised. Journal of the American Academy of Psychiatry and the Law, 29(1), 89–95.
• Grann, M., Langström, N., Tengström, A., & Kullgren, G. (1999). Psychopathy (PCL-R) predicts violent recidivism among criminal offenders with personality disorders in Sweden. Law and Human Behavior, 23(2), 205–217. https://doi.org/10.1023/A:1022378902598
• Hare, R. D. (1991). The Hare Psychopathy Checklist–Revised. Multi-Health Systems.
• Hare, R. D. (1993). Without conscience: The disturbing world of the psychopaths among us. Guilford Press.
• Hare, R. D. (2003). The Hare Psychopathy Checklist–Revised: 2nd edition (PCL-R). Multi-Health Systems.
• Hare, R. D., Clark, D., Grann, M., & Thornton, D. (2000). Psychopathy and the predictive validity of the PCL-R: An international perspective. Behavioral Sciences & the Law, 18(5), 623–645. https://doi.org/10.1111/j.2044-8333.1998.tb00355.x
• Kiehl, K. A. (2006). A cognitive neuroscience perspective on psychopathy: Evidence for paralimbic system dysfunction. Psychiatry Research, 142(2–3), 107–128. https://doi.org/10.1016/j.psychres.2005.09.013
• Leistico, A. M. R., Salekin, R. T., DeCoster, J., & Rogers, R. (2008). A large-scale meta-analysis relating the Hare measures of psychopathy to antisocial conduct. Law and Human Behavior, 32(1), 28–45. https://doi.org/10.1007/s10979-007-9096-6
• Lykken, D. T. (1957). A study of anxiety in the sociopathic personality. The Journal of Abnormal and Social Psychology, 55(1), 6–10. https://doi.org/10.1037/h0047232
• Neumann, C. S., Hare, R. D., & Newman, J. P. (2007). The super-ordinate nature of the psychopathy checklist-revised. Journal of Personality Disorders, 21(2), 102–117. https://doi.org/10.1521/pedi.2007.21.2.102
• Skeem, J. L., & Cooke, D. J. (2010). Is criminal behavior a central component of psychopathy? Conceptual directions for resolving the debate. Psychological Assessment, 22(2), 433–445. https://doi.org/10.1037/a0018512

13. Items of the Scale (Questionnaire)