Psychopathy, traumatic exposure, and lifetime posttraumatic stress

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Jochem Willemsen, Julie De Ganck and Paul VerhaeghePsychopathy, Traumatic Exposure, and Lifetime Posttraumatic Stress

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International Journal ofOffender Therapy and

Comparative Criminology56(4) 505 –524

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1Ghent University, Belgium

Corresponding Author:Jochem Willemsen, Ghent University, Henri Dunantlaan 2, B-9000 Ghent, Belgium Email: [email protected]

Psychopathy, Traumatic Exposure, and Lifetime Posttraumatic Stress

Jochem Willemsen1, Julie De Ganck1, and Paul Verhaeghe1

Abstract

This study examined two theoretical models on the interaction between psychopathy, traumatic exposure, and lifetime posttraumatic stress in a sample of 81 male detainees. In Model 1, the interpersonal and affective features of psychopathy were assumed to protect against posttraumatic stress. In Model 2, the lifestyle and antisocial traits of psychopathy were assumed to lead to a lifestyle that increases the risk of traumatic exposure and subsequent posttraumatic stress. The authors found significant negative bivariate associations between Psychopathy Checklist–Revised (PCL-R) total, Interpersonal and Affective facet scores, and posttraumatic stress. Model 1 was confirmed, as they found the interaction between the Affective facet and traumatic exposure had a significant negative effect on posttraumatic stress. Model 2 was rejected. The authors’ findings confirm that the interpersonal and affective features of psychopathy are associated with an emotional deficit and that the affective features of psychopathy are crucial for understanding the relationship between psychopathy and anxiety.

Keywords

psychopathy, emotional deficit, trauma, posttraumatic stress, anxiety

Psychopathy is a severe personality disorder that consists of interpersonal, affective, and behavioral features. On the interpersonal level, psychopaths are grandiose, arro-gant, callous, dominant, superficial, and manipulative. Affectively, they are short tem-pered, unable to form strong emotional bonds with others, and lacking in guilt or anxiety. These interpersonal and affective features are associated with a socially deviant lifestyle

Articles



506 International Journal of Offender Therapy and Comparative Criminology 56(4)

characterised by irresponsible, impulsive, and rule-breaking behavior and a tendency to ignore or violate social conventions and mores (Cleckley, 1976; Hare, 2003, 2006; Hare & Neumann, 2005, 2008). The predominant instrument to assess this personality disorder is the Hare Psychopathy Checklist–Revised (PCL-R; Hare, 2003). Although the PCL-R has engendered a tremendous body of empirical research in the past, it has recently been argued that more theory-driven research is needed for the advancement of clinical psychology in general (Strauss & Smith, 2009) and our understanding of the psychopathy construct in particular (Skeem & Cooke, 2010). Our study adopted a theoretically driven approach to what has been identified as one of the key questions in the field of psychopathy, notably the relationship between psychopathy and anxiety (Hare & Neumann, 2008; Lilienfeld, 1994; Patrick, 2006; Skeem & Cooke, 2010). The aim of this study was to investigate the association between psychopathy, as defined by Hare (2003), and a specific form of anxiety, notably posttraumatic stress, by testing two theoretical models on the relationship between traumatic exposure, posttraumatic stress, and psychopathy.

Posttraumatic stress disorder (PTSD) is an anxiety disorder that potentially devel-ops after exposure to an event in which the individual experienced, witnessed, or was confronted with either actual or threatened loss of life or serious injury invoking a response of fear, helplessness, or horror. According to the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association [APA], 1994), the diagnosis of PTSD requires that three clusters of symptoms (reex-periencing the traumatic event, numbing of affect and avoidance of trauma-related stimuli, and hyperarousal) are present for at least 1 month, causing significant distress or impairment (APA, 2000). However, there is considerable evidence that many indi-viduals in reaction to a traumatic event display some symptoms of posttraumatic stress, without developing full PTSD (Helzer, Robins, & McEvoy, 1987; Stein, Walker, Hazen, & Forde, 1997). Such subthreshold posttraumatic stress is clinically relevant, as it appears to be associated with significant and long-standing impairment (Cukor, Wyka, Jayasinghe, & Difede, 2010). PTSD has been shown to be more prevalent in a sentenced prison population than in the general population, with different studies find-ing sentenced prison population–prevalence rates between 4% and 21% (Goff, Rose, Rose, & Purves, 2007). This high prevalence rate is not surprising, as prisoners appear to be exposed to more traumatic events during childhood and/or adulthood than indi-viduals in the general population (Jordan, Schlenger, Fairbank, & Caddell, 1996; Urbaniok, Endrass, Noll, Vetter, & Rossegger, 2007; Weeks & Widom, 1998). Prison and general populations do not show differences in terms of the types of life events considered to be traumatic (Collins & Bailey, 1990; Gibson et al., 1999). However, there is emerging evidence for a traumatic event that is specific to offender popula-tions, notably the commission of a violent crime. Some studies suggest that PTSD can directly arise from the commission of a violent or sexual offence, at least in forensic psychiatric patients (Gray et al., 2003; Papanastassiou, Waldron, Boyle, & Chesterman, 2004; Pham, 2012). However, the notion of offence-related PTSD remains



Willemsen et al. 507

equivocal regarding offenders in a general prison population (Payne, Watt, Rogers, & McMurran, 2008).

In the research literature, psychopathy has been linked in different ways to anxiety in general and to posttraumatic stress in particular, because psychopathy is a multifac-eted concept. Hare (1991) originally proposed a two-factor model for the PCL-R, in which the core personality traits (“selfish, callous, and remorseless use of others”) and the behavioral features of psychopathy (“chronically unstable, antisocial, and socially deviant lifestyle”) are distinguished. There is considerable evidence that these two factors are differentially related to indications of internalising psychopathology. The personality factor is associated with lower anxiety (Blonigen et al., 2010; Harpur, Hare, & Hakstian, 1989; Hicks & Patrick, 2006) and greater psychological well-being (Verona, Patrick, & Joiner, 2001), whereas the behavioral factor is associated with higher anxiety (Blonigen et al., 2010; Hicks & Patrick, 2006) and risk of suicide (Verona et al., 2001). Later factor-analytical studies on the PCL-R (Cooke & Michie, 2001; Hare, 2003; Hare & Neumann, 2005) concur that the personality factor can be broken down into two facets: an Interpersonal and an Affective facet. Furthermore, there is general agreement that the behavioral factor also consists of two components—a Lifestyle and an Antisocial facet—although some authors (Cooke & Michie, 2001; Skeem & Cooke, 2010) have argued that the Antisocial facet should not be included in the PCL-R, as it is associated too strongly with criminal behavior.

One line of research posits a negative association between the interpersonal and affective personality features of psychopathy and posttraumatic stress. Proponents of this reasoning build on the proposition that psychopathy is marked by a lack of anxiety and/or fear (Cleckley, 1976; Lykken, 1995). In his seminal work The Mask of Sanity (1976), Cleckley stated that psychopathy is characterised by a fundamental emotional deficit, making it impossible to experience serious and deeply moving emotional states, and anxiety in particular. Some argue that this fundamental emo-tional deficit prevents the psychopathic individual from developing posttraumatic stress. Some of the factors advanced by cognitive and behavioral theories on the psychogenesis of PTSD are fear conditioning (neutral stimuli present during the traumatic event acquire fear-eliciting properties through association with the trau-matic event), avoidance behavior (avoidance of conditioned stimuli prevents extinc-tion of the association with the traumatic event; Keane, Zimering, & Caddell, 1985; Mowrer, 1960), and attentional bias (attention is abnormally sensitive to threat-related stimuli; Foa & Riggs, 1993). Indeed, evidence suggests that when exposed to reminders of traumatic events, trauma-exposed participants with PTSD exhibit greater physiological responses than trauma-exposed participants without PTSD (Blanchard, Hickling, Taylor, Loos, & Gerardi, 1994). Furthermore, individuals with PTSD develop stronger and more resistant conditioned physiological responses to aversive stimuli that are not related to the traumatic event than trauma-exposed indi-viduals without PTSD (Orr et al., 2000). Finally, individuals with PTSD are more eas-ily distracted by emotional cues when performing an experimental task (Bar-Haim,




Lamy, Pergamin, Bakermans-Kranenburg, & van Ijzendoorn, 2007). However, psy-chopathy is associated with more difficulty in acquiring conditioned physiological fear responses (Birbaumer et al., 2005; Hare & Quinn, 1971; Lykken, 1957), less ability to learn to avoid responding to specific stimuli that lead to punishment (Blair et al., 2004; Lykken, 1957; Newman & Schmitt, 1998), and less distraction by emo-tional stimuli during experimental tasks (Christianson et al., 1996; Michell, Richell, Leonard, & Blair, 2006). These studies suggest that the psychophysiological func-tioning of highly psychopathic individuals and individuals with PTSD is exactly the inverse. Moreover, recent theoretical models have linked both the emotional deficit of psychopathy (Daversa, 2010; Fowles & Dindo, 2006; Patrick, 2007) and the psy-chogenesis of PTSD (Rauch, Shin, & Phelps, 2006) to a neurobiological deficit at the level of the amygdale. Psychopathy is associated with a hyporeactive amygdale, resulting in lower performance on functions that are known to recruit the amygdale, such as aversive conditioning and avoidance learning. However, PTSD is associated with a hyperreactive amygdale, making individuals more susceptible to fear condi-tioning, and thus more likely to develop posttraumatic stress symptoms after a trau-matic event. Based on this line of reasoning, Blair and Mitchell (2009) conclude that psychopathy is in some functional respects the inverse of PTSD. Accordingly, we posit a first model in which the interpersonal and affective features of psychopathy are negatively associated with posttraumatic stress because these personality fea-tures protect individuals from the impact of traumatic exposure: As psychopathic individuals are less likely to develop conditioned fear, to avoid unpleasant stimuli, and to focus on threat stimuli, the impact of traumatic exposure may be less signifi-cant for them than nonpsychopathic individuals. This model is represented graphi-cally in Figure 1.

To our knowledge, this model has never been tested in scientific literature, although four studies have reported on the association between psychopathy and posttraumatic stress. Moeller and Hell (2003) studied a sample of 102 inmates and did not find a single case of PTSD in a group of psychopaths (defined as a score > 25 on the PCL-R), although PTSD could be diagnosed in a small proportion of the nonpsychopathic group.

Traumatic Exposure

Interpersonal/Affective Traits

Posttraumatic Stress

Figure 1. Model 1: The interpersonal and affective traits of psychopathy as protector against posttraumatic stress




Similarly, Pham (2012) found a strong negative association between the PCL-R scores (in particular the affective features of psychopathy) and acute stress following a trau-matic experience in forensic psychiatric patients. However, Blackburn, Logan, Donnelly, and Renwick (2003) found a significantly higher prevalence of PTSD in psychopaths (defined as a score > 25 on the PCL-R) in their sample of forensic psychi-atric patients, and Kubak and Salekin (2009) found a significant positive association between ratings on the Psychopathy Checklist–Youth Version (Forth, Kosson, & Hare, 2003) and symptoms of PTSD in child and adolescent offenders.

A second line of research advances that the lifestyle and antisocial features of psychopathy are positively related to posttraumatic stress. According to this model, the impulsive and antisocial traits of psychopathy lead to a lifestyle that increases the risk of encountering stressful life events (e.g., a serious accident, being a victim of violence, incarceration, etc.; Frick, Lilienfeld, Ellis, Loney, & Silverthorn, 1999). The positive association between psychopathy and posttraumatic stress might there-fore be explained by increased traumatic exposure. This model is represented graph-ically in Figure 2.

The complete model as represented in Figure 2 has, as far as we know, never been tested. However, there has been previous research on the separate paths in this model. Indeed, some researchers have found a positive association between psychopathy and increased traumatic exposure (Dembo et al., 2007; Moeller & Hell, 2003; however not by Pham, 2012). Individuals from the general population with a history of behavioral problems before the age of 15 were more likely to have been beaten or mugged during the past 18 months and more likely to have seen combat if they served in Vietnam than those who reported little or no history of delinquency (Helzer et al., 1987), and child-hood conduct disorder has also been shown to predict traumatic exposure (Koenen et al., 2002). Furthermore, a number of researches have established the positive associa-tion between criminal behavior, antisocial personality disorder, substance abuse, and PTSD, especially in men (Helzer et al., 1987; O’Toole, Marshall, Schureck, & Dobson, 1998; Sareen, Stein, Cox, & Hassard, 2004; Sierles, Chen, Messing, Besyner, & Taylor, 1986). This link has been established in community samples but scarcely in samples of incarcerated men (Gibson et al., 1999).

Lifestyle/Antisocial Traits

Traumatic Exposure

Posttraumatic Stress

Figure 2. Model 2: The lifestyle and antisocial traits of psychopathy increase traumatic exposure and subsequent posttraumatic stress




This study contributes to the literature on three points. First, we focused exclu-sively on traumatic exposure during adulthood. Most previous research does not dis-tinguish between traumatic exposure during childhood or adolescence and traumatic exposure during adulthood, although their association to psychopathy is conceptually different. Some theoretical and empirical studies have suggested that early traumatic exposure plays a role in the aetiology of psychopathy, as it might alter the neurobiol-ogy of the brain and contribute to the core affective deficit of psychopathy (Daversa, 2010; Farrington, 2006; Lang, af Klinteberg, & Alm, 2002; Marshall & Cooke, 1999; Poythress, Skeem, & Lilienfeld, 2006; Weiler & Widom, 1996). However, in this study, we did not address the question of the aetiology of psychopathy but rather focused on the association between psychopathy and posttraumatic stress during adulthood. Although we acknowledge that early traumatic experiences might further complicate the precise relationship between psychopathy and posttraumatic stress, we preferred to test two clear-cut theoretical models. Our second contribution to the literature lies in the fact that the two models outlined above have never been tested before. By test-ing theoretical models instead of bivariate associations, this study responds to the recent call from more theory-driven research in the field of psychopathy (Skeem & Cooke, 2010). Third, we examine the association between psychopathy and posttrau-matic stress on a more detailed level. All previously mentioned studies—except Pham (2012)—only provide information on the association between the PCL-R total scores and the categorical diagnosis of PTSD. We include the four facets of the PCL-R (Interpersonal, Affective, Lifestyle, and Antisocial) in our analyses (Hare & Neumann, 2005), and we consider posttraumatic stress as a dimensional variable by focussing on symptoms of posttraumatic stress rather than on categorical diagnoses of PTSD. In that way, we include clinically relevant levels of subthreshold posttrau-matic stress in our analyses, and we avoid losing information by dichotomising a continuous variable.

MethodParticipants

Participants were 81 male inmates recruited from the population of two prisons in Flanders (Belgium). The following inclusion criteria were applied: conventional com-petency in Dutch, no psychotic symptoms, not being on remand, and being declared fully responsible for one’s actions. Of the sample, 27% were convicted for (attempted) manslaughter or murder, 25% for a violent crime (robbery, assault, or battery), 41% for a sexual crime (indecent assault or rape of a minor or adult), and 7% for other crimes (drugs, fraud, or burglary). Inmates participated on a voluntary basis after supplying written informed consent. No incentive was given. The racial and ethnic composition of the sample was 84% White, 14% North Africans, and 2% other. The mean age of the sample at the time of the interview was 39.8 years (SD = 12.17, range = 20-73 years).




Instruments

Psychopathy. Psychopathy was assessed via ratings on the PCL-R (Hare, 2003). Rat-ings were based on information gathered from a semistructured clinical interview and review of file information. The interviewer was a clinical psychologist (first author) who received training in administering and scoring the PCL-R. To check the interrater reliability, PCL-R ratings made by clinical psychologists working in the prisons were made available to the authors. In that way, we obtained independent PCL-R ratings for 42% of the participants. Interrater reliability as determined by the intraclass correlation coefficient (absolute agreement) for a single rating, using a two-way random effects model, was .79 for the Interpersonal/Affective factor, .76 for the Lifestyle/Antisocial factor, and .82 for the PCL-R total score. Cronbach’s alpha as an index of internal con-sistency was good for the Interpersonal facet (.82), the Affective facet (.77), the Life-style facet (.78), the Antisocial facet (.69), and the total PCL-R scale (.83). The mean PCL-R total score in our sample was 22.9 (SD = 8.51, range = 1-36); 32% of the sample scored below 20 on the PCL-R, and 28% of the sample scored equal to or above the cutoff of 30. We tested mean differences on PCL-R scores as a function of the index offence and racial/ethnic origin. We found that the Lifestyle and Antisocial facets dif-fered significantly as a function of index offence, Welch F(3, 22.75) = 4.99, p < .01 and Welch F(3, 17.05) = 9.08, p < .05, respectively. Post hoc analyses using the Games–Howell test indicated that the average score on the Lifestyle facet was significantly higher in detainees who were convicted for a violent crime (M = 7.87, SD = 1.27) than those who were convicted for a sexual crime (M = 5.94, SD = 3.40) or homicide (M = 5.60, SD = 3.14), and the average score on the Antisocial facet was significantly higher in detainees who were convicted for a violent crime (M = 7.13, SD = 1.63) than those who were convicted for a sexual crime (M = 4.04, SD = 2.78) or homicide (M = 4.74, SD = 3.27). No significant mean differences between PCL-R scores were found as a function of racial/ethnic origin. We also calculated Pearson correlations between age and PCL-R scores and found a significant negative correlation for the Lifestyle facet (r = −.40, p < .01) and the Antisocial facet (r = −.47, p < .01).

Lifetime symptoms of posttraumatic stress. The participants were interviewed regard-ing symptoms of reexperiencing, avoidance, and hyperarousal using the Structured Clinical Interview for DSM-IV-R Axis 1 Disorders (SCID-I). The presence of reexpe-riencing, avoidance, and hyperarousal symptoms was scored on a three-point scale from 0 (absent) to 1 (uncertain) to 2 (present). A Posttraumatic Stress Scale was cal-culated by adding up the scores on all 17 symptoms. This resulted in a scale with a mean of 3.6 (SD = 7.10, range = 0-23, skewness = 1.73 with SE = 0.27, and kurtosis = 1.48 with SE = 0.53) and that showed good internal consistency (Cronbach’s α = .94). Six of the 81 participants (7%) had a lifetime categorical diagnosis of PTSD.

Audiotapes of the SCID-I interviews were independently rated by a student with a bachelor’s degree in clinical psychology. For 46% of the sample, dual SCID-I ratings were made by the student. Interrater reliability of the individual symptoms as deter-mined by the kappa coefficient ranged from .58 for the symptom “markedly diminished




interest or participation in significant activities” to 1.00 for the symptoms “efforts to avoid thoughts, feelings, or conversations associated with the trauma,” “irritability or outbursts of anger,” and “hypervigilance.” The intraclass correlation coefficient (abso-lute agreement) was .96 for the Posttraumatic Stress Scale.

Traumatic exposure during adulthood. The first question of the section on PTSD in the SCID-I contains a list of critical incidents that one might have experienced or been aware that a loved one had experienced. In response to this question, the partici-pants recited all the potentially traumatic events they had encountered during their lives. We only counted responses that were in accordance with the A1 criterion and that occurred after the age of 18. The responses could be classified into five catego-ries: the index offence (violent or sexual offence; reported by 21% of the sample), accidents (traffic accident, fire, near drowning, climbing accident; reported by 9.9% of the sample), being a victim of aggression (being attacked or threatened; reported by 7.4% of the sample), witnessing the death or wounding of someone (witnessed murder, death, or dead body or saw person seriously hurt, see atrocities; reported by 13.6% of the sample), and serious illness or sudden death of relative (serious illness or death of child, unexpected death of family member or close friend; reported by 32.1% of the sample). A frequency score for traumatic exposure was calculated by totalling all potentially traumatic events reported. In our sample, 62% of the partici-pants had experienced at least one potentially traumatic event in accordance with the A1 criterion, and the mean frequency score was 1.2 (SD = 1.83, range = 0-10, skew-ness = 3.15 with SE = 0.27, and kurtosis = 12.11 with SE = 0.53). A versatility score for traumatic exposure was calculated by adding the number of above-mentioned categories of traumatic events that were reported by participants. The mean versatil-ity score was 0.84 (SD = 0.80, range = 0-3, skewness = 0.60 with SE = 0.27, and kurtosis = −0.31 with SE = 0.53).

Statistical AnalysisFirst, we calculated bivariate associations between the PCL-R scores, frequency, and versatility of traumatic exposure and posttraumatic stress. As posttraumatic stress are count data (number of symptoms) with overdispersion (the variance is greater than the mean), we used bivariate negative binomial regression analyses in which posttrau-matic stress is regressed onto frequency of traumatic exposure, versatility of traumatic exposure, and the PCL-R total and facet scores separately (Coxe, West, & Aiken, 2009). We also tested the bivariate associations between frequency of traumatic expo-sure, versatility of traumatic exposure, and the PCL-R total and facet scores. Next, we tested the two models. The first model was tested as a moderator analysis. First, trau-matic exposure (predictor) and the Interpersonal/Affective facets of the PCL-R (mod-erators) were entered in a multivariate negative binomial regression model with posttraumatic stress (outcome). Next, we entered the product of predictor and mod-erator and checked whether the moderator effect was significant. The second model was tested through a mediation analysis. First we tested whether there is a positive




association between the Lifestyle and Antisocial facets of the PCL-R (predictors) and posttraumatic stress (outcome). If this were the case, we would then test whether this positive association could be explained by traumatic exposure (mediator). Significant moderator and/or mediator effects were further tested as recommended by Holmbeck (2002). We followed the recommendations made by Frazier, Tix, and Barron (2004) for conducting moderator and mediator analyses.

ResultsThe bivariate associations between PCL-R scores, frequency of traumatic exposure, versatility of traumatic exposure, and posttraumatic stress symptoms are reported in Table 1. There was a significant positive association between versatility of traumatic exposure and posttraumatic stress but not between frequency of traumatic exposure and posttraumatic stress. For each unit increase on the versatility of traumatic expo-sure scale (i.e., for each additional type of traumatic event reported), the number of posttraumatic symptoms increases with a factor of 1.46, exp(.377). There was a sig-nificant negative association between PCL-R total scores and posttraumatic stress. For each unit increase on the PCL-R total scale, the number of posttraumatic symp-toms decreases with a factor of 0.97, exp(−.026). At the level of the facets of psy-chopathy, we see a significant negative association between the Interpersonal and the Affective facets and posttraumatic stress. For each unit increase on these facet scales, the number of posttraumatic symptoms decreases with a factor of 0.87, exp(−.142) and 0.88, exp(−.125), respectively. The Lifestyle and Antisocial facet were not

Table 1. Bivariate Associations Between PCL-R Scores, Frequency of Traumatic Exposure, Versatility of Traumatic Exposure, and Posttraumatic Stress

Posttraumatic stress Frequency trauma Versatility trauma

B SE B Wald χ2a B SE B Wald χ2 B SE B Wald χ2

Frequency trauma .054 .081 0.44 Versatility

trauma.377 .170 4.91*

PCL-R total -.026 .014 2.74* .008 .018 0.23 .005 .019 0.08Interpersonal

facet-.142 .042 11.63** .062 .052 1.45 -.008 .056 0.02

Affective facet -.125 .047 7.45** .027 .065 0.18 -.010 .068 0.02Lifestyle facet .002 .041 0.00 -.009 .053 0.03 .016 .058 0.08Antisocial facet .039 .040 0.99 .010 .051 0.04 .058 .056 1.06Note: PCL-R = Psychopathy Checklist–Revised.aThe degrees of freedom of all Wald χ2 tests in this table are equal to 1.*p ≤ .05. **p ≤ .01.




Table 2. Testing the Moderator Effects of Model 1 Using Negative Binomial Regression

Step and variable B SE B Wald χ2 df p

Step 1 Interpersonal facet -.139 .042 10.85 1 .00 Versatility of traumatic exposure .343 .169 4.13 1 .04Step 2 Interpersonal facet × Versatility of traumatic events -.011 .058 0.03 1 .85Step 1 Affective facet -.105 .048 4.75 1 .03 Versatility of traumatic exposure .273 .176 2.40 1 .12Step 2 Affective facet × Versatility of traumatic events -.178 .068 6.81 1 .01

significantly associated with posttraumatic stress. PCL-R total and facet scores were not related to frequency of traumatic exposure and versatility of traumatic exposure.

We then proceeded to test the two models on the association between traumatic exposure, psychopathy, and posttraumatic stress. The first model stipulates that the interpersonal and affective traits of psychopathy function as protective factors against the development of posttraumatic stress. This means that the Interpersonal and Affective facets of psychopathy negatively moderate the association between traumatic expo-sure and the subsequent development of posttraumatic symptoms. As we previously found a significant positive association between versatility of traumatic exposure and posttraumatic stress, but not frequency of traumatic exposure, we use versatility of traumatic exposure as the predictor variable. The results from two negative binomial regression analyses are reported in Table 2.

For the model with the Interpersonal facet and versatility of traumatic exposure, we found in Step 1 that both the predictor and the moderator had a significant main effect on posttraumatic stress. For each unit increase on the Interpersonal facet scale, the number of posttraumatic symptoms decreases with a factor of 0.87, exp(−.139), whereas for each unit increase on the Versatility of Traumatic Exposure scale, the number of posttraumatic symptoms increases with a factor of 1.41, exp(.343). This result paral-lels the bivariate associations found earlier. When the product term of the Interpersonal facet and versatility of traumatic exposure was entered in the model in Step 2, this interaction term appeared to have no significant effect on posttraumatic stress. So no evidence was found for an interaction effect. Similar analysis was done for the Affective facet. Step 1 resulted in a model whereby the Affective facet has a significantly nega-tive main effect on posttraumatic stress. This means that for each unit increase on the Affective facet scale, the number of posttraumatic symptoms decreases with a factor of 0.90, exp(−.105). In this model, the versatility of traumatic events had no significant effect on posttraumatic stress. Step 2 resulted in a model that shows the interaction term has a significant negative effect on posttraumatic stress. Negative binomial




regression does not allow for a direct comparison between nested models (i.e., the regression models with and without the interaction term) and does not allow for the calculation of a R2 statistic as index for the variance explained in the outcome vari-able by predictor, mediator, and interaction term (Coxe et al., 2009). However, the significant negative effect of the interaction term is evidence for the moderating effect of the Affective facet on the relationship between versatility of traumatic exposure and posttraumatic stress.

Following the procedure described by Holmbeck (2002), we conducted two post hoc regression analyses to probe this moderator effect. Prior to these analyses, we computed two conditional moderator variables by adding one standard deviation to the centered Affective facet (low Affective facet) and by subtracting one standard devia-tion from the centered Affective facet (high Affective facet). With these conditional variables, we conducted two negative binomial regression analyses, each of which included the main effect for versatility of traumatic exposure, the main effect for one conditional moderator variable, and the interaction effect of these two variables. The results of the regression analysis with low Affective facet as a conditional moderator indicated that there was a significant positive association between the degree of post-traumatic stress and versatility of traumatic exposure (B = .693, SE B = .243, p < .01); the results of the regression analysis with high Affective facet as a conditional mod-erator indicated that the degree of posttraumatic stress was not significantly associated with versatility of traumatic exposure (B = −.168, SE B = .237, p > .05). Regression lines depicting the relationship between versatility of traumatic exposure and post-traumatic stress as moderated by the Affective facet are plotted in Figure 3. These results demonstrate that at higher levels of the Affective facet, the impact of versatility of traumatic exposure on posttraumatic stress is mitigated.

The second model postulates that a positive association between the Lifestyle and Antisocial facets of the PCL-R and posttraumatic stress could be explained by the increased traumatic exposure in individuals with an impulsive-irresponsible and anti-social lifestyle.

Table 3 contains the results necessary to examine Model 2. Following the proce-dure described by Frazier et al. (2004), we first tested the effect of the Lifestyle/Antisocial facet on posttraumatic stress through negative binomial regression (Step 1). The results were not statistically significant. To establish that the Lifestyle and Antisocial facets are related to versatility of traumatic exposure, we regressed the latter on the former variables (Step 2). Here again, we found no significant results. In Step 3, we regressed posttraumatic stress simultaneously on the Lifestyle/Antisocial facet and on versatility of traumatic exposure. The regression coefficients associated with the rela-tionship between versatility of traumatic events and posttraumatic stress was signifi-cant in both cases, but the regression coefficients associated with the relationship between the Lifestyle/Antisocial facets and posttraumatic stress were not statistically significant. Although most of the results in Table 3 are not significant, this does not exclude a mediation effect. MacKinnon, Lockwood, Hoffman, West, and Sheets (2002) have demonstrated that the requirement that results are significant in Step 1, 2,




Figure 3. Regression lines for relationships between versatility of traumatic exposure and posttraumatic stress as moderated by the PCL-R affective facet

and 3 decreases the ability to test for mediation effects, especially in small samples. They advise that a formal test (Sobel test) of the indirect effect be performed, and Preacher and Leonardelli (2010) provide an online calculator to perform this test. The Sobel test indicated that the indirect effect of the Lifestyle facet on posttraumatic stress through versatility of traumatic exposure is not significant, Sobel test (z) = .274, p = .78. Likewise, the indirect effect of the Antisocial facet on posttraumatic stress through versatility of traumatic exposure is not significant, Sobel test (z) = .845, p = .40. This means that there is no evidence for Model 2, according to which a positive




Table 3. Testing the Mediation Effects of Model 2 Using Negative Binomial Regression

Step and variable B SE B Wald χ2 df p

Step 1 Outcome: Posttraumatic stress Predictor: Lifestyle facet .002 .041 0.00 1 .97Step 2 Outcome: Versatility of traumatic exposure Predictor: Lifestyle facet .016 .058 0.08 1 .78Step 3 Outcome: Posttraumatic stress Mediator: Versatility of traumatic events .039 .171 4.92 1 .03 Predictor: Lifestyle facet .007 .041 0.03 1 .87Step 1 Outcome: Posttraumatic stress Predictor: Antisocial facet .039 .040 0.99 1 .32Step 2 Outcome: Versatility of traumatic exposure Predictor: Antisocial facet .058 .056 1.06 1 .30Step 3 Outcome: Posttraumatic stress Mediator: Versatility of traumatic events .353 .174 4.10 1 .04 Predictor: Antisocial facet .032 .040 0.63 1 .43

relationship between the Lifestyle/Antisocial facet of the PCL-R and posttraumatic stress is mediated by versatility of traumatic exposure.

ConclusionIt has long been postulated by clinicians and researchers that psychopathy is charac-terised by a lack of anxiety and/or fear (Cleckley, 1976; Lykken, 1957), and this idea is the basis for several of the most recent theories on psychopathy (Daversa, 2010; Fowles & Dindo, 2006; Lykken, 1995; Patrick, 2007). However, results from empiri-cal studies on this topic have been inconsistent (Hare, 2003; Schmitt & Newman, 1999), and the role of anxiety in the psychopathy construct remains unclear (Hare & Neumann, 2008). The primary aim of this study was to investigate the association between psychopathy and posttraumatic stress by testing two theoretical models that specify differing relationships between traumatic exposure, posttraumatic stress, and psychopathy. First, we found through bivariate negative binomial regression analyses that the Interpersonal and Affective facets of the PCL-R are negatively associated with posttraumatic stress. This implies that the core personality features of psychopa-thy are protective factors against the development of posttraumatic stress. This finding




contributes to the view that an essential affective deficit underlies the interpersonal and affective features of psychopathy and that these personality features are crucial for understanding the relationship between psychopathy and anxiety (Cleckley, 1976; Daversa, 2010; Fowles & Dindo, 2006; Patrick, 2007).

To find more specific indications for the protective role of psychopathy, we tested whether the interpersonal and affective traits moderate the effect of traumatic exposure on posttraumatic stress (Model 1). We found that the Affective facet of the PCL-R, but not the Interpersonal facet, and traumatic exposure had a significant interaction effect on posttraumatic stress. This finding confirms the construct validity of the distinction made by factor-analytical studies between interpersonal and affective features within the psy-chopathic personality (Cooke & Michie, 2001; Hare, 2003; Hare & Neumann, 2005).

From the perspective that the development of posttraumatic stress can be conceptu-alized as a fear-conditioning process (Mowrer, 1960; Rauch et al., 2006), this finding confirms the theory that the affective features of psychopathy are characterised by low fear conditionability (Fowles & Dindo, 2006; Lykken, 1995; Patrick, 2007). A number of experimental studies have established this theory (Birbaumer et al., 2005; Blair et al., 2004; Hare & Quinn, 1971; Lykken, 1957; Newman & Schmitt, 1998), but our research replicates this finding with real-life unconditioned stimuli (traumatic exposure) and clinically relevant conditioned response (posttraumatic stress). Furthermore, our find-ing lends support to the assertion that psychopathy is characterised by a deficient cog-nitive processing of emotional information (Blair & Mitchell, 2009). Traumatic events might have less psychopathological consequences for high-psychopathic individuals because they are less inclined to interpret these events as threatening and horrifying. There is considerable experimental evidence for deficits in the cognitive processing of emotional information by psychopathic individuals (Christianson et al., 1996; Michell et al., 2006). For instance, Christianson et al. (1996) presented neutral slides (e.g., a woman bicycling on the street in front of a car) and negative emotional slides (e.g., a woman lying beside her bicycle on the street in front of a car bleeding from a head injury) to high- and low-psychopathic offenders. During a subsequent memory test, nonpsycho-pathic offenders recalled more central than peripheral details of emotional slides, whereas the psychopathic offenders recalled equally well the central and peripheral details of emotional slides. Apparently, the process of focussing on emotional infor-mation typically found in nonpsychopathic individuals is less operative in psycho-pathic individuals. However, when the offenders were asked to consciously evaluate the emotional valence of the slides, both psychopathic and nonpsychopathic offenders were able to rate the emotional slides as being more negative than the neutral slides. Christianson et al. conclude that there is a discrepancy between the conscious verbal rating of negative emotional events and the automatic processing of emotional infor-mation. In a similar vein, we found in our study that participants who score high on the Affective facet of the PCL-R were able to enumerate a number of emotional (i.e., traumatic) events when asked to do so (see Table 1: the nonsignificant cor-relation between the Affective facet and frequency and versatility of traumatic




exposure) but that the impact of these events is mitigated by the Affective facet (possibly because of different cognitive processing of these emotional events).

Consistent with previous research in offender samples (Jordan et al., 1996; Urbaniok et al., 2007; Weeks & Widom, 1998), the degree of exposure to traumatic events dur-ing adulthood was quite high in our sample. Serious illness or sudden death of a rela-tive was the most common type of traumatic event reported. Inspection of the individual cases that reported this type of traumatic event revealed that 60% involved the acci-dental death of a family member or friend, 33% involved the suicide of a family mem-ber or friend, and only 7% of the cases involved the violent death of a family member or friend through crime. The second most-commonly reported type of traumatic event was the index offence, suggesting that a violent or sexual offence can be experienced as traumatic by the offender himself or herself. However, previous research on offend-ers from general prison populations has indicated that higher levels of traumatic expo-sure prior to the offence increases the degree of offence-related PTSD, which makes the direct relationship between the offence and PTSD more complex (Payne et al., 2008). Some authors have claimed that an impulsive, irresponsible, and antisocial life-style would be associated with an elevated risk for traumatic exposure during adult-hood (Frick et al., 1999). However, we found no significantly positive relationship between the Lifestyle and Antisocial facet of the PCL-R and frequency or versatility of traumatic experiences. This finding is in contradiction with Dembo et al. (2007) and Moeller and Hell (2003; but in line with Pham, 2012). However, these studies did not distinguish between traumatic exposure during adulthood and childhood. It is possible that the Lifestyle and Antisocial facets are positively related to stressful life events, such as familial and marital discord, financial and professional problems, and so on, rather than with traumatic events in terms of the DSM-IV A1 criterion. Such stressful life events might very well induce general maladaptive functioning, stress and negative emotions, rather than posttraumatic stress. Further research might focus on this topic. However, in this study, we found no evidence that the behavioral features of psy-chopathy have an indirect effect on posttraumatic stress through the mediating factor of traumatic exposure. Therefore, Model 2 on the association between psychopathy and posttraumatic stress was rejected.

Several limitations of the present study should be noted. First, we did not include traumatic exposure during childhood or adolescence in this study. Although there are theoretical and empirical indications that early traumatic exposure plays a role in the aetiology of psychopathy (Daversa, 2010; Farrington, 2006; Lang et al., 2002; Marshall & Cooke, 1999; Poythress et al., 2006; Weiler & Widom, 1996), and that traumatic exposure at a younger age increases sensitization to the effects of later trau-matic events (Koenen et al., 2002), the focus of this study was not on the aetiology of psychopathy and posttraumatic stress. Our aim was to investigate the relationship between psychopathy and posttraumatic stress, and restricting traumatic exposure to adulthood made it possible to test two clear-cut conceptual models. Second, the reli-ability of our measurement of traumatic events might be impeded by the retrospective design and reliance on primarily self-report information. We tried to minimize the




impact of this design by using (semi)structured interview formats. Third, the mean PCL-R total score of 22.9 in our sample is considerably higher than generally found in European samples (e.g., Coid et al., 2009; Hare, 2003), which indicates that our sam-ple is not representative for the population of European or even Belgian detainees. However, in our opinion, the marked presence of psychopathy in our sample is not a threat to the validity of our results. To study a clinical phenomenon, it is important that this phenomenon is present in a considerable portion of the sample. Furthermore, the range in PCL-R scores in our sample was very large. Future research might focus on which of the above-mentioned mechanisms determine the moderating role of the emo-tional deficit in psychopathy (deficient fear conditioning, avoidance learning, or atten-tional bias) or investigate other psychopathological consequences of traumatic exposure, such as agoraphobia and depression (Gabriel et al., 2007). It seems to us that the topic of traumatic exposure and posttraumatic stress offers a theoretically and clin-ically relevant field of research outside the laboratory for studying psychopathic per-sonality traits as a factor of robustness against internalising psychopathology.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disor-ders (4th ed.). Washington, DC: Author.

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disor-ders (4th ed., text rev.). Washington, DC: Author.

Bar-Haim, Y., Lamy, D., Pergamin, L., Bakermans-Kranenburg, M. J., & van Ijzendoorn, M. H. (2007). Threat-related attentional bias in anxious and nonanxious individuals: A meta-analytic study. Psychological Bulletin, 133, 1-24.

Birbaumer, N., Viet, R., Lotze, M., Erb, M., Hermann, C., Grodd, W., & Flor, H. (2005). Defi-cient fear conditioning in psychopathy. Archives of General Psychiatry, 62, 799-805.

Blackburn, R., Logan, C., Donnelly, J., & Renwick, S. (2003). Personality disorders, psychopa-thy and other mental disorders: Co-morbidity among patients at English and Scottish high-security hospitals. Journal of Forensic Psychiatry & Psychology, 14, 111-137.

Blair, R. J. R., & Mitchell, D. G. V. (2009). Psychopathy, attention and emotion. Psychological Medicine, 39, 543-555.

Blair, R. J. R., Mitchell, D. G. V., Leonard, A., Budhani, S., Peschardt, K. S., & Newman, C. (2004). Passive avoidance learning in individuals with psychopathy: Modulation by reward but not by punishment. Personality and Individual Differences, 37, 1179-1192.




Blanchard, E. B., Hickling, E. J., Taylor, A. E., Loos, W. R., & Gerardi, R. J. (1994). The psychophysiology of motor vehicle accident related posttraumatic stress disorder. Behavior Therapy, 25, 453-467.

Blonigen, D. M., Patrick, C. J., Douglas, K. S., Poythress, N. G., Skeem, K. S., Lilienfeld, S. O., . . . Krueger, R. F. (2010). Multimethod assessment of psychopathy in relation to factors of internalising and externalising from the Personality Assessment Inventory: The impact of method variance and suppressor effects. Psychological Assessment, 22, 96-107.

Christianson, S. A., Forth, A. E., Hare, R. D., Strachan, C., Lidberg, L., & Thorell, L. H. (1996). Remembering details of emotional events: A comparison between psychopathic and non-psychopathic offenders. Personality and Individual Differences, 20, 437-443.

Cleckley, H. (1976). The mask of sanity (5th ed.). St. Louis, MO: Mosby.Coid, J., Yang, M., Ullrich, S., Roberts, A., Moran, P., Bebbington, P., . . . Hare, R. D. (2009).

Psychopathy among prisoners in England and Wales. International Journal of Law and Psychiatry, 32, 134-141.

Collins, J. J., & Bailey, S. L. (1990). Traumatic stress disorder and violent behaviour. Journal of Traumatic Stress, 3, 203-220.

Cooke, D. J., & Michie, C. (2001). Refining the construct of psychopathy: Towards a hierarchical model. Psychological Assessment, 13, 171-188.

Coxe, S., West, S. G., & Aiken, L. S. (2009). The analysis of count data: A gentle introduction to Poisson regression and its alternatives. Journal of Personality Assessment, 91, 121-136.

Cukor, J., Wyka, K., Jayasinghe, N., & Difede, J. (2010). The nature and course of subthreshold PTSD. Journal of Anxiety Disorders, 24, 918-923.

Daversa, M. T. (2010). Early environmental predictors of the affective and interpersonal construct of psychopathy. International Journal of Offender Therapy and Comparative Crim-inology, 54, 6-21.

Dembo, R., Jainchill, N., Turner, C., Fong, C., Farkas, S., & Childs, K. (2007). Levels of psy-chopathy and its correlates: A study of incarcerated youth in three states. Behavioral Sci-ences & the Law, 25, 717-738.

Farrington, D. P. (2006). Family background and psychopathy. In C. J. Patrick (Ed.), Handbook of psychopathy (pp. 229-250). New York, NY: Guildford.

Foa, E. B., & Riggs, D. S. (1993). Post-traumatic stress disorder in rape victims. In J. Oldham, M. B. Riba, & A. Tasman (Eds.), American Psychiatric Press Review of Psychiatry (Vol. 12, pp. 273-303). Washington, DC: American Psychiatric Press.

Forth, A. E., Kosson, D. S., & Hare, R. D. (2003). Hare Psychopathy Checklist: Youth Version (PCL-YV). Toronto, ON, Canada: Multi-Health Systems.

Fowles, D. C., & Dindo, L. (2006). A dual-deficit model of psychopathy. In C. J. Patrick (Ed.), Handbook of psychopathy (pp. 14-34). New York, NY: Guildford.

Frazier, P. A., Tix, A. P., & Barron, K. E. (2004). Testing moderator and mediator effects in counseling psychology research. Journal of Counseling Psychology, 51, 115-134.

Frick, P. J., Lilienfeld, S. O., Ellis, M., Loney, B., & Silverthorn, P. (1999). The association between anxiety and psychopathy dimensions in children. Journal of Abnormal Child Psychology, 27, 383-392.




Gabriel, R., Ferrando, L., Corton, E. S., Mingote, C., Garcia-Camba, E., Liria, A. F., & Galea, S. (2007). Psychopathological consequences after a terrorist attack: An epidemiological study among victims, the general population, and police officers. European Psychiatry, 22, 339-346.

Gibson, L. E., Holt, J. C., Fondacaro, K. M., Tang, T. S., Powell, T. A., & Turbitt, E. L. (1999). An examination of antecedent traumas and psychiatric comorbidity among male inmates with PTSD. Journal of Traumatic Stress, 12, 473-484.

Goff, A., Rose, E., Rose, S., & Purves, D. (2007). Does PTSD occur in sentenced prison popula-tions? A systematic literature review. Criminal Behaviour and Mental Health, 17, 152-162.

Gray, N. S., Carman, N. G., Rogers, P., MacCulloch, M. J., Hayward, P., & Snowden, R. J. (2003). Post-traumatic stress disorder caused in mentally disordered offenders by the com-mitting of a serious violent or sexual offence. Journal of Forensic Psychiatry & Psychology, 14, 27-43.

Hare, R. D. (1991). The Hare Psychopathy Checklist-Revised. Toronto, ON, Canada: Multi-Health Systems.

Hare, R. D. (2003). The Hare Psychopathy Checklist-Revised (2nd ed.). Toronto, ON, Canada: Multi-Health Systems.

Hare, R. D. (2006). Psychopathy: A clinical and forensic overview. Psychiatric Clinics of North America, 29, 709-724.

Hare, R. D., & Neumann, C. S. (2005). Structural models of psychopathy. Current Psychiatry Reports, 7, 57-64.

Hare, R. D., & Neumann, C. S. (2008). Psychopathy as a clinical and empirical construct. Annual Review of Clinical Psychology, 4, 217-246.

Hare, R. D., & Quinn, M. J. (1971). Psychopathy and automatic conditioning. Journal of Abnormal Psychology, 77, 223-235.

Harpur, T. J., Hare, R. D., & Hakstian, A. R. (1989). Two-factor conceptualization of psychopa-thy: Construct validity and assessment implications. Psychological Assessment, 1, 6-17.

Helzer, J. E., Robins, L. N., & McEvoy, L. (1987). Post-traumatic stress disorder in the general population: Findings of the Epidemiological Catchment Area Survey. New England Journal of Medicine, 317, 1630-1634.

Hicks, B. M., & Patrick, C. J. (2006). Psychopathy and negative emotionality: Analyses of suppressor effects reveal distinct relations with emotional distress, fearfulness, and anger-hostility. Journal of Abnormal Psychology, 115, 276-287.

Holmbeck, G. N. (2002). Post-hoc probing of significant moderational and mediational effects in studies of pediatric populations. Journal of Pediatric Psychology, 27, 87-96.

Jordan, B. K., Schlenger, W. E., Fairbank, J. A., & Caddell, J. M. (1996). Prevalence of psychi-atric disorders among incarcerated women: Convicted felons entering prison. Archives of General Psychiatry, 53, 513-519.

Keane, T. M., Zimering, R. T., & Caddell, R. T. (1985). A behavioral formulation of PTSD in Vietnam veterans. Behavior Therapist, 8, 9-12.

Koenen, K. C., Harley, R., Lyons, M. J., Wolfe, J., Simpson, J. C., Goldberg, J., . . . Tsuang, M. T. (2002). A twin registry study of familial and individual risk factors for trauma exposure and posttraumatic stress disorder. Journal of Nervous and Mental Disease, 190, 209-218.




Kubak, F. A., & Salekin, R. T. (2009). Psychopathy and anxiety in children and adolescents: New insights on developmental pathways to offending. Journal of Psychopathology and Behavioral Assessment, 31, 271-284.

Lang, S., af Klinteberg, B., & Alm, P. O. (2002). Adult psychopathy and violent behavior in males with early neglect and abuse. Acta Psychiatrica Scandinavica, 106(Suppl. 412), 93-100.

Lilienfeld, S. O. (1994). Conceptual problems in the assessment of psychopathy. Clinical Psy-chology Review, 14, 17-38.

Lykken, D. T. (1957). A study of anxiety in the sociopathic personality. Journal of Abnormal and Social Psychology, 55, 6-10.

Lykken, D. T. (1995). The antisocial personalities. Mahwah, NJ: Erlbaum.MacKinnon, D. P., Lockwood, C. M., Hoffman, J. M., West, S. G., & Sheets, V. (2002). A com-

parison of methods to test mediation and other intervening variable effects. Psychological Methods, 7, 83-104.

Marshall, L. A., & Cooke, D. J. (1999). The childhood experiences of psychopaths: A retrospec-tive study of familial and societal factors. Journal of Personality Disorders, 13, 211-225.

Michell, D. G., Richell, R. A., Leonard, A., & Blair, R. J. (2006). Emotion at the expense of cog-nition: Psychopathic individuals outperform controls on an operant response task. Journal of Abnormal Psychology, 115, 559-566.

Moeller, A. A., & Hell, D. (2003). Affective disorder and “psychopathy” in a sample of younger male delinquents. Acta Psychiatrica Scandinavica, 107, 203-207.

Mowrer, O. H. (1960). Learning theory and behaviour. New York, NY: Wiley.Newman, J. P., & Schmitt, W. A. (1998). Passive avoidance in psychopathic offenders: A rep-

lication and extension. Journal of Abnormal Psychology, 107, 527-532.Orr, S. P., Metzger, L. J., Lasko, N. B., Macklin, M. L., Peri, T., & Pitman, R. K. (2000). De

novo conditioning in trauma-exposed individuals with and without posttraumatic stress dis-order. Journal of Abnormal Psychology, 109, 290-298.

O’Toole, B. I., Marshall, R. P., Schureck, R. J., & Dobson, M. (1998). Posttraumatic stress disor-der and comorbidity in Australian veterans: Risk factors, chronicity, and combat. Australian and New Zealand Journal of Psychiatry, 32, 32-42.

Papanastassiou, M., Waldron, G., Boyle, J., & Chesterman, L. P. (2004). Post-traumatic stress disorder in mentally ill perpetrators of homicide. Journal of Forensic Psychiatry & Psychology, 15, 66-75.

Patrick, C. J. (2006). Back to the future: Cleckley as a guide to the next generation of psychopa-thy research. In C. J. Patrick (Ed.), Handbook of psychopathy (pp. 605-617). New York, NY: Guildford.

Patrick, C. J. (2007). Getting to the heart of psychopathy. In H. Hervé & J. C. Yuille (Eds.), The psychopath: Theory, research and practice (pp. 207-252). New York, NY: Lawrence Erlbaum.

Payne, E., Watt, A., Rogers, P., & McMurran, M. (2008). Offence characteristics, trauma histo-ries and post-traumatic stress disorder symptoms in life sentenced prisoners. British Journal of Forensic Practice, 10, 17-25.




Pham, H. T. (2012). Psychopathy and traumatic stress. Journal of Personality Disorders, 26(2), 213-225.

Poythress, N. G., Skeem, J. L., & Lilienfeld, S. O. (2006). Associations among early abuse, dissociation, and psychopathy in an offender sample. Journal of Abnormal Psychology, 115, 288-297.

Preacher, K., & Leonardelli, G. (2010). Calculation for the Sobel test: An interactive calculation tool for mediation tests. Retrieved November 30, 2010, from http://people.ku.edu/~preacher/sobel/sobel.htm

Rauch, S. L., Shin, L. M., & Phelps, E. A. (2006). Neurocircuitry models of posttraumatic stress disorder and extinction: Human neuroimaging research—Past, present, and future. Biologi-cal Psychiatry, 60, 376-382.

Sareen, J., Stein, M. B., Cox, B. J., & Hassard, S. T. (2004). Understanding comorbidity of anxi-ety disorders with antisocial behavior: Findings from two large community surveys. Journal of Nervous and Mental Disease, 192, 178-186.

Schmitt, W. A., & Newman, J. P. (1999). Are all psychopathic individuals low-anxious? Journal of Abnormal Psychology, 108, 353-358.

Sierles, F. S., Chen, J. J., Messing, M. L., Besyner, J. K., & Taylor, M. A. (1986). Concurrent psychiatric illness in non-Hispanic outpatients diagnosed as having posttraumatic stress dis-order. Journal of Nervous and Mental Disease, 174, 171-173.

Skeem, J. L., & Cooke, D. J. (2010). One measure does not a construct make: Directions toward reinvigorating psychopathy research—Reply to Hare and Neumann (2010). Psychological Assessment, 22, 455-459.

Stein, M. B., Walker, J. R., Hazen, A. L., & Forde, D. R. (1997). Full and partial posttraumatic stress disorder: Findings from a community survey. American Journal of Psychiatry, 154, 1114-1119.

Strauss, M. E., & Smith, G. T. (2009). Construct validity: Advances in theory and methodology. Annual Review of Clinical Psychology, 5, 1-25.

Urbaniok, F., Endrass, J., Noll, T., Vetter, S., & Rossegger, A. (2007). Posttraumatic stress disorder in a Swiss offender population. Swiss Medical Weekly, 137, 151-156.

Verona, E., Patrick, C. J., & Joiner, T. E. (2001). Psychopathy, antisocial personality, and suicide risk. Journal of Abnormal Psychology, 110, 462-470.

Weeks, R., & Widom, C. S. (1998). Self-reports of early childhood victimization among incar-cerated adult male felons. Journal of Interpersonal Violence, 13, 346-361.

Weiler, B. L., & Widom, C. S. (1996). Psychopathy and violent behaviour in abused and neglected young adults. Criminal Behaviour and Mental Health, 6, 253-271.



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Psychopathy, traumatic exposure, and lifetime posttraumatic stress