Physical Abuse Explains Sex Differences in the Link Between Psychopathy and Aggression

Abstract

Psychopathy has long been associated with aggression. However, few studies have looked at differences between men and women. Studies that do exist demonstrate that psychopathy differentially relates to aggression in men and women and indicate that environmental factors may play a significant role in influencing these associations. A key environmental factor is a history of lifetime physical abuse (LPA), which has been linked to aggressive behavior in both men and women. The aim of the present study was to test if psychopathy differentially predicted physical, verbal, and indirect aggression in men and women, and if these associations were moderated by LPA. In a large community sample of men (n = 369) and women (n = 204), we assessed the 4-facet model of psychopathy (Interpersonal, Affective, Lifestyle, Antisocial) with the Psychopathy Checklist: Screening Version, LPA with the Addiction Severity Index, and self-report aggression with the Aggression Questionnaire. Results revealed sex differences and similarities. Physical aggression was associated with the affective facet of psychopathy in both men and women, though in different directions based on the moderating effects of LPA. Verbal aggression was associated with higher antisocial facet scores and LPA for men and not women. Finally, indirect aggression was associated with the antisocial facet of psychopathy for men, and the interpersonal facet for women, and these associations were not moderated by LPA. In women, low antisocial facet scores and no LPA were found to be protective for indirect aggression. These results show that LPA and psychopathy generally increase the risk of aggression, but the interaction between LPA and psychopathy differentiates the risk of aggression forms for men and women. These sex differences highlight the need for female-responsive interventions to target sex-specific risk factors for aggressive behavior.

Keywords

physical abuse child abuse community violence violence exposure women offenders

Psychopathy has been long associated with aggressive and violent behavior. Even though the community prevalence of psychopathy is low (men = 1%-2%; women = 0.3%-0.7%), estimates show that these individuals are responsible for a significant proportion (20%-40%) of all violent crime (Coid & Yang, 2011; Hare & Neumann, 2008). Not only are psychopaths responsible for habitual violence, but compared with nonpsychopaths, they engage in more cruel, sadistic, and gratuitous violence (Robertson & Knight, 2014). Because of the chronic level of offending and reoffending, psychopathy has been proposed to be one of the most expensive psychiatric disorders, costing society about US$460 billion annually (Kiehl & Hoffman, 2011). Because such a small number of individuals cost society a great deal, studying the mechanisms behind psychopathy-related aggression has begun to receive greater attention, which will help inform and refine intervention efforts aimed to break the link between psychopathy and aggression. Indeed, this is a worthwhile endeavor, as targeting 1.2% of the general population may lead to a 20% to 40% reduction in violence. A possible mechanism behind psychopathy-related aggression is exposure to physical abuse. Exposure to physical abuse is strongly linked to the perpetration of violence (Trauffer & Widom, 2017) and psychopathy (Krischer & Sevecke, 2008), which, when coupled together, may increase the risk of aggressive behavior. Because there are notable sex differences in the links between psychopathy and aggression (Thomson, 2018), and physical abuse and aggression (Sigelman, Berry, & Wiles, 1984), evaluating the moderating role of physical abuse on the psychopathy–aggression link may offer a deeper understanding into the mechanisms that explain male and female differences in psychopathy-related aggression.

Psychopathy and Aggression

Psychopathy is a disorder traditionally consisting of personality (e.g., interpersonal-affective; Factor 1) and behavioral (e.g., impulsive-antisocial; Factor 2) traits. As measured by the Psychopathy Checklist, the construct of psychopathy includes four facets, interpersonal (i.e., grandiosity, superficial charm, manipulative), affective (i.e., lack of remorse, shallow affect, callous lack of empathy), lifestyle (i.e., boredom susceptibility, impulsivity, lack of realistic long-term goals), and antisocial (i.e., poor behavioral controls, juvenile and adult delinquency). Unlike total scores or cut-off scores, the facet scores provide a more sensitive approach to understanding associations with violence and aggression, as well as sex differences in these associations (Vassileva et al., 2018). Although some have criticized the inclusion of antisocial behavior within the construct of psychopathy as being a tautological measure (Skeem & Cooke, 2010), within the research realm of understanding violence, the 4-facet model has proved beneficial for developing risk models. For example, including the antisocial facet in predictive models controls for the effects of past criminality, thus, any associations found among the psychopathy facets and aggression are independent of past criminality. For instance, in a mixed sample of men and women, Vitacco, Neumann, and Jackson (2005) found the affective and antisocial facets were moderately strong predictors of violence, which highlights the sensitivity of the 4-facet model when predicting aggressive behavior. Furthermore, the 4-facet construct has emerged as an important construct for understanding sex differences in the association with different forms of aggression and violence (Thomson, 2018, 2020), as well as the neurobiological mechanisms of psychopathy-related aggression and violence in women (Thomson, Kiehl, & Bjork, 2018).

Studies focusing on either just men or women have contributed to the growing body of literature that there are sex differences in psychopathy-related aggression. For example, in a Dutch male psychiatric sample, both the antisocial and lifestyle facets were correlated with physical aggression but the affective and interpersonal facets were not (Zwets, Hornsveld, Neumann, Muris, & van Marle, 2015). This finding is consistent in Canadian male offenders, whereby only the antisocial and lifestyle facets predicted violence (Olver, Neumann, Wong, & Hare, 2013). Thus, research from male samples most reliably finds the antisocial and lifestyle facets best predict physical aggression, while the interpersonal and affective facets do not. In contrast, drawing from the limited research on women, the antisocial and affective facets seem to play an equally important role in aggression and have been shown to prospectively predict future prison violence, previous violent crimes, and community-based physical aggression and interpersonal violence (Thomson, 2020; Thomson et al., 2018; Thomson, Towl, & Centifanti, 2016; Vassileva et al., 2018). Thus, the antisocial facet seems to be predictive of physical aggression for men and women, while the affective facet is only predictive for women. There has been little research to understand the associations of psychopathy with forms of aggression beyond physical aggression, such as indirect or verbal aggression. Furthermore, while psychopathy has been regarded as one of the most challenging disorders to treat (Lewis, 2018; Polaschek & Skeem, 2018), it may be possible for interventions to target the links between psychopathy and aggression to reduce the number of victims; thus, it is paramount for research to begin to explore the mechanisms behind psychopathy-related aggression, and if these mechanisms are sex-specific. Here, we propose that a potential sex-specific mechanism is exposure to physical abuse.

Physical Abuse

Childhood maltreatment has been suggested to play a key role in the development of psychopathy. For example, one of the earliest longitudinal studies found boys and girls who were abused/neglected had higher Psychopathy Checklist–Revised (PCL-R) scores almost 20 years later (Weiler & Widom, 1996). Dargis et al. (2016) found in a sample of male offenders that psychopathy scores on the PCL-R were related to childhood abuse, but only the antisocial facet was associated with overall childhood trauma and physical abuse. No associations were found for the interpersonal or affective facets. This is consistent with prior findings on male prisoners (Poythress, Skeem, & Lilienfeld, 2006) and a community sample of adults (Durand & de Calheiros Velozo, 2018). Therefore, it seems that physical abuse is most strongly predictive of the development of antisocial psychopathic traits, but it remains unknown how physical abuse contributes to the risk of psychopathy-related aggression.

The occurrence of physical abuse has received a great deal of attention in recent years, with many studies showing that exposure to physical abuse puts a person at risk for a host of long-term vulnerabilities, such as poor physical health and mental health, and interpersonal problems (Malinosky-Rummell & Hansen, 1993; Springer, Sheridan, Kuo, & Carnes, 2007), as well as being at greater risk of becoming both the victim and perpetrator of violence (Maldonado, Watkins, & DiLillo, 2015; Richards, Tillyer, & Wright, 2017). A possible explanation of the link between physical abuse and aggression may be because exposure to physical abuse during childhood and adulthood may occur in a hostile and invalidating environment, which may impact emotion regulation capabilities (Masten & Coatsworth, 1998). Indeed, victims of physical abuse have been found to have errors in social information processing (specifically, cue interpretation), and poor emotion regulation (Teisl & Cicchetti, 2008). Furthermore, these cognitive and emotional processing deficits have been found to explain the relation between exposure to physical abuse and aggressive and disruptive behavior (Teisl & Cicchetti, 2008). In support of these findings, biological vulnerability to emotion dysregulation (i.e., resting parasympathetic activity) has been found to mediate the link between borderline personality disorder (thought to stem from an invalidating environment) and aggressive behavior (Thomson & Beauchaine, 2018). With regard to psychopathy, poor emotion regulation has also been found to moderate the link between affective psychopathic traits and interpersonal violence in young women (Thomson et al., 2018). Thus, exposure to lifetime physical abuse (LPA) may impact the individual’s ability to regulate and manage emotions, as well as the ability to adequately interpret social cues, placing them at greater risk for aggressive behavior. Thus, physical abuse may then strengthen the association between psychopathy and specific forms of aggression, particularly physical aggression.

Aggression Forms and Psychopathy

Aggression is defined as behavior that causes intentional harm to people or oneself (Anderson & Bushman, 2002). Within the construct of aggression, there is further classification based on the function, such as proactive (i.e., goal-directed) or reactive (i.e., provoked), as well as the form of behavior, such as overt (i.e., physical, verbal) or covert (i.e., indirect/relational) forms. Physical aggression and violence include the acts of causing physical harm to another person or property, and verbal aggression includes verbal abuse, mocking, profanity, and character attacks. In contrast to these overt forms, indirect aggression is a more discrete method for causing harm to another person, by spreading rumors and gossiping about someone behind their back, or ignoring and excluding the person. Indirect aggression is used when the costs of physical or verbal aggression are high (Archer & Coyne, 2005, p. 212; Björkqvist, 1994). Typically, men engage in higher levels of overt forms of aggression, while levels of indirect aggression are often found to be similar between men and women (Czar, Dahlen, Bullock, & Nicholson, 2011; Schmeelk, Sylvers, & Lilienfeld, 2008), although some have found higher rates among women (Thomson, Bozgunov, Psederska, & Vassileva, 2019). With regard to psychopathy, there is limited research exploring associations between psychopathy facets and aggression forms, particularly verbal and indirect aggression. Based on the available research, in a sample of U.S. service members, both the antisocial and interpersonal features of psychopathy were associated with verbal and physical aggression (Anestis, Green, Arnau, & Anestis, 2017). Using a latent profile analysis to group individuals based on self-report psychopathy scores, Colins, Fanti, Salekin, and Andershed (2017) showed that compared with adults who scored low on all psychopathy facets, adults who scored highest on the interpersonal features and antisocial features had higher levels of verbal aggression, and there were no sex differences. Regarding indirect aggression, using the Psychopathic Personality Inventory (PPI), Schmeelk et al. (2008) found indirect aggression was associated with antisocial and lifestyle psychopathic traits, and this association was not moderated by sex. In summary, it seems that the antisocial facet is predictive of physical aggression, the interpersonal and antisocial facets are associated with verbal aggression, the antisocial and lifestyle facets are associated with indirect aggression, and these associations are consistent for both men and women. However, the most consistent sex difference appears to be that physical aggression is predicted by higher affective facet scores in women only.

The Present Study

The aim of the present study was to assess sex differences in the association between the 4-facet model of psychopathy (interpersonal, affective, lifestyle, antisocial) and aggression (physical, verbal, and indirect), and to see if these associations were moderated by LPA. Because a significant amount of research has been conducted on prisoners, and risk factors for aggression may be contextual (Thomson, Vassileva, et al., 2019), we aimed to understand the link between psychopathy and aggression in a community sample. Studying community populations provides the opportunity to test risk factors for aggression when individuals are living more freely in society, as opposed to prisoners or inpatients who are supervised 24/7. In addition, individuals involved in the criminal justice system inevitably have a history of antisocial behavior, which may influence the association between psychopathy and antisocial behavior (e.g., aggression). Despite the limited literature, we were able to develop several hypotheses. We expected the antisocial facet to be associated with all forms of aggression, and the interpersonal facet to be associated with indirect aggression for both men and women. We also expected to find sex differences, with higher scores on the affective facet to be associated with higher levels of physical aggression for women, but not for men. Because physical abuse is thought to impact emotion regulation capabilities, we expected moderation effects for more overt aggression forms (physical and verbal). Specifically, we expected physical abuse to moderate the association between the affective facet and physical aggression for women, and the association between the antisocial facet and physical and verbal aggression for both men and women.

Method

Participants and Data Collection

Data were collected as part of a larger ongoing study investigating impulsivity among substance dependent individuals in Bulgaria. The data were collected in two sessions on 2 separate days, which included a combination of clinical interviews, self-report surveys, and neurocognitive tasks. Testing was conducted by an experienced team of psychologists at the Bulgarian Addictions Institute, Sofia, Bulgaria. All participants provided informed consent. The study was approved by the Institutional Review Boards of Virginia Commonwealth University and the Medical University in Sofia on behalf of the Bulgarian Addictions Institute. Participants were recruited via flyers placed at substance abuse clinics, therapeutic communities, nightclubs, bars, and cafés in Bulgaria, as well as through the study’s web page and Facebook page. The sample consisted of healthy controls with no history of substance abuse or dependence and individuals who had a past history of opiate or stimulant dependence as defined by Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) criteria. All participants were abstinent at the time of testing, which was verified by breathalyzer test for alcohol and urine toxicology screen for amphetamines, methamphetamines, cocaine, opiates, methadone, cannabis, benzodiazepines, barbiturates, and Ecstasy/Molly (MDMA).

The sample included 369 male and 204 female Bulgarian adults between the ages of 18 and 45 with a mean age of 27.86 (SD = 6.40). Most participants (88%) had achieved a high school diploma, and 52% were currently employed. A total of 63% of men and 41% of women met the diagnostic criteria for substance dependence. Men with a past/current substance dependence/abuse met the DSM-IV diagnostic criteria for the following substance use disorders: alcohol (32%), sedatives (4.5%), cannabis (50%), stimulants (40%), opiates (34%), cocaine (6%), and hallucinogens (3%). Women with a past/current dependence/abuse met the DSM-IV diagnostic criteria for the following substance use disorders: alcohol (18%), sedatives (4%), cannabis (25%), stimulants (28%), opiates (18%), cocaine (5%), and hallucinogens (3%). A total of 7% of the entire sample met the diagnostic cut-off for psychopathy per the Psychopathy Checklist: Screening Version (PCL:SV > 18).

Assessment Instruments

Psychopathy

The PCL:SV (Hart, Cox, & Hare, 1995) was administered to participants by a trained team of researchers initially trained by J.V., the author of the Bulgarian version of the PCL-R with its publisher Multi-Health Systems, and by Robert Hare, the author of the PCL:SV. The PCL:SV is a 12-item semistructured interview based on the PCL-R, which has been adapted and validated cross-culturally (Douglas, Strand, Belfrage, Fransson, & Levander, 2005), including in a Bulgarian sample (Wilson, Abramowitz, Vasilev, Bozgunov, & Vassileva, 2014). Items are scored on a 3-point scale (0 = absent; 1 = somewhat present; 2 = definitely present) and summed to provide total scores ranging from 0 to 24 points. An in-depth psychometric analysis of the Bulgarian version of the PCL:SV with a subset of the current Bulgarian sample revealed good fit and adequate internal consistency of the 4-facet model of psychopathy (Wilson et al., 2014). Interrater reliability (Intraclass Correlation Coefficient [ICC]) was found to be good for the Interpersonal (ICC = .79), Affective (ICC = .91), Lifestyle (ICC = .87), and Antisocial facets (ICC = .93).

Substance dependence

Lifetime substance dependence was assessed using the Substance Abuse Module of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I; First, Spitzer, Gibbon, & Williams, 2007). Raters assessed the presence of DSM-IV symptoms of alcohol, cannabis, opiate, and stimulant abuse and dependence using a 3-point scale (0 = not present, 1 = subthreshold, 2 = present). A diagnosis of substance dependence was made if the participant displayed three or more of the substance dependence criteria within a 12-month period. Assessments were conducted by experienced clinicians trained by J.V. and G.V.

LPA

LPA was assessed using the physical abuse item on the Addiction Severity Index–Lite Version (ASI-Lite; McLellan, Cacciola, Carise, & Coyne, 1999). The ASI is a semistructured interview assessing problem areas for patients with substance use disorders. The physical abuse item assesses if the individual has been physically abused at some point in their life (e.g., physical harm such as slapping, punching, kicking, hitting with an object, assaulting with a knife or other weapon, etc.). Answers are reported and coded as “yes” (1) or “no” (0). The ASI also assesses physical abuse occurring within a 30-day period, as well as sexual abuse (lifetime and in the past 30 days). Due to low prevalence of lifetime and 30-day sexual abuse (2.4% and 1%, respectively), and physical abuse in the past 30 days (1.6%), we chose to focus on LPA history (30% prevalence). The ASI is an effective and reliable measure of abuse history (Langeland, Draijer, & van den Brink, 2003; Regier et al., 2017).

Aggression

The Aggression Questionnaire (AQ; Buss & Warren, 2000) measures physical aggression, verbal aggression, indirect aggression, as well as anger and hostility. The anger and hostility subscales are risk factors for aggression rather than direct measures of aggression. Thus, only the physical, verbal, and indirect aggression subscales were used in the present study. The physical aggression subscale measures physical force when expressing aggression using eight items (e.g., “If somebody hits me, I hit back”). The verbal aggression subscale assesses the tendency to engage in verbal arguments/insults using five items (“When people annoy me, I may tell them what I think of them”). The indirect aggression subscale measures aggression while avoiding direct confrontation using six items (e.g., “. . . spread gossip about people I don’t like”). In line with prior research (Gresham, Melvin, & Gullone, 2016), our scale reliabilities were adequate to good (α = .69-.83). We used the recently validated Bulgarian version of the AQ (Popov et al., 2016).

Data Analytic Plan

Statistical analyses were conducted using R (R Core Team, 2017). A series of hierarchical linear regressions was conducted to test the associations between LPA, psychopathic traits, and aggression forms. Regressions followed the same structure for physical, verbal, and indirect aggression: Step 1 included age, Substance Dependence, and LPA. Step 2 added the PCL:SV facets to Step 1. Step 3 added the interaction terms between lifetime history of physical abuse and the four PCL:SV facets. To assess sex differences, separate analyses were conducted for men and women. Significant interactions were probed using simple slopes analysis (Aiken & West, 1991).

Results

Physical Aggression

Results of the hierarchical linear regression predicting physical aggression are displayed in Table 1. For women, on Step 1, F(3, 204) = 8.75, p < .001, physical abuse (p = .002) and substance dependence were significant (p = .002). Step 2 added the PCL:SV facets, F(7, 204) = 11.29, p < .001. The affective (p = .002) and antisocial facets were significant (p = .001). Step 3 added the interaction between the PCL:SV facets and physical abuse, F(11, 204) = 7.59, p < .001. The only interaction to emerge as significant was between the affective facet and physical abuse (p = .039). Simple slopes analysis (see Figure 1a) indicated that high affective traits predicted physical aggression for women with a history of physical abuse (p < .001), but not for women without physical abuse history (p = .665).

Table 1.

Psychopathy and Lifetime History of Physical Abuse as Predictors of Physical Aggression.

	Physical Aggression: Women				Physical Aggression: Men
	B	SE B	β	∆R²	B	SE B	β	∆R²
Step 1				.12***				.17***
Age	−0.08	0.21	−.02		−0.12	0.24	−.03
Substance Dependence	0.72	0.23	.22**		1.53	0.21	.36***
Physical Abuse	1.60	0.52	.21**		1.33	0.44	.15**
Step 2				.17***				.18***
Age	−0.18	0.20	−.06		−0.32	0.22	−.06
Substance Dependence	−0.37	0.28	−.11		−0.26	0.26	−.06
Physical Abuse	0.80	0.49	.11		0.78	0.40	.09^†
PCL:SV Interpersonal	0.21	0.34	.05		0.04	0.21	.01
PCL:SV Affective	1.16	0.37	.25**		0.17	0.25	.04
PCL:SV Lifestyle	−0.04	0.32	−.01		0.25	0.27	.06
PCL:SV Antisocial	1.47	0.42	.36**		2.19	0.31	.54***
Step 3				.02				.02*
Age	−0.21	0.21	−.07		−0.33	0.21	−.07
Substance Dependence	−0.32	0.28	−.10		−0.34	0.26	−.08*
Physical Abuse	1.12	0.58	.15		1.11	0.43	.13
PCL:SV Interpersonal	0.35	0.38	.08		0.18	0.26	.04*
PCL:SV Affective	0.26	0.58	.06		0.70	0.31	.17
PCL:SV Lifestyle	0.14	0.45	.04		0.02	0.32	.01
PCL:SV Antisocial	1.58	0.53	.39**		2.00	0.36	.49***
Interpersonal × Physical Abuse	−0.40	0.79	−.05		−0.51	0.45	−.07
Affective × Physical Abuse	1.60	0.77	.24*		−1.53	0.52	−.23**
Lifestyle × Physical Abuse	−0.17	0.67	−.02		0.73	0.58	.10
Antisocial × Physical Abuse	−0.42	0.78	−.05		0.69	0.58	.10

Note. PCL:SV = Psychopathy Checklist: Screening Version.

†

p = .05. *p < .05. **p < .01. ***p < .001.

Figure 1.

The moderating effect of physical abuse on the association between affective psychopathic traits and physical aggression. (a) Women: The moderating effect of physical abuse on the association between affective psychopathic traits and physical aggression. (b) Men: The moderating effect of physical abuse on the association between affective psychopathic traits and physical aggression.

For men, Step 1 was significant, F(3, 369) = 25.42, p < .001. Physical abuse (p = .002) and substance dependence (p < .001) were significant. Step 2 added the PCL:SV facets, F(7, 369) = 28.45, p < .001. The antisocial facet was significant (p < .001). Step 3 added the interaction between the PCL:SV facets and history of physical abuse, F(11, 369) = 19.72, p < .001. The only interaction to emerge as significant was between the affective facet and physical abuse (p = .003). Simple slopes analysis (see Figure 1b) showed that physical aggression was predicted by low affective traits in men with physical abuse history (p = .047), while lower levels of physical aggression were associated with low affective traits in men without physical abuse history (p = .024).

Verbal Aggression

Results of the hierarchical linear regression predicting verbal aggression for men and women are displayed in Table 2. For women, Step 1 was not significant, F(3, 204) = 1.50, p = .215, and none of the predictors at this step were significant. Step 2 added the PCL:SV facets, F(7, 204) = 3.23, p = .003. Only the antisocial facet was significant (p = .003). Step 3 added the interaction between the PCL:SV facets and physical abuse, F(11, 204) = 2.19, p = .017. However, no significant interactions emerged.

Table 2.

Psychopathy and Lifetime History of Physical Abuse as Predictors of Verbal Aggression.

	Verbal Aggression: Women				Verbal Aggression: Men
	B	SE B	β	∆R²	B	SE B	β	∆R²
Step 1				.02				.04**
Age	−0.31	0.20	−.11		−0.24	0.22	−.06
Substance Dependence	0.30	0.22	.10		0.58	0.19	.16**
Physical Abuse	−0.29	0.49	−.04		0.55	0.39	.07
Step 2				.08**				.01
Age	−0.39	0.20	−.14		−0.28	0.22	−.07
Substance Dependence	−0.44	0.29	−.15		0.31	0.26	.09
Physical Abuse	−0.65	0.50	−.10		0.50	0.40	.07
PCL:SV Interpersonal	0.30	0.35	.08		0.33	0.22	.10
PCL:SV Affective	−0.07	0.38	−.02		−0.16	0.25	−.05
PCL:SV Lifestyle	0.06	0.33	.02		−0.07	0.27	−.02
PCL:SV Antisocial	1.29	0.43	.35**		0.39	0.31	.12
Step 3				.01				.02
Age	−0.42	0.21	−.15*		−0.25	0.22	−.06
Substance Dependence	−0.46	0.29	−.16		0.23	0.26	.06
Physical Abuse	−0.71	0.60	−.11		0.51	0.44	.07
PCL:SV Interpersonal	0.39	0.39	.10		0.55	0.27	.16*
PCL:SV Affective	0.03	0.59	.01		0.02	0.32	.01
PCL:SV Lifestyle	−0.32	0.46	−.09		0.06	0.33	.02
PCL:SV Antisocial	1.54	0.54	.42**		−0.01	0.37	.00
Interpersonal × Physical Abuse	−0.37	0.81	−.05		−0.63	0.46	−.11
Affective × Physical Abuse	−0.03	0.79	.00		−0.56	0.53	−.10
Lifestyle × Physical Abuse	0.86	0.68	.13		−0.34	0.59	−.05
Antisocial × Physical Abuse	−0.35	0.80	−.05		1.29	0.59	.23*

Note. PCL:SV = Psychopathy Checklist: Screening Version.

p < .05. **p < .01. ***p < .001.

For men, Step 1 was significant, F(3, 369) = 4.91, p = .002. Substance dependence was significant (p = .002). Step 2 added the PCL:SV facets, F(7, 369) = 2.85, p = .007; however, none of the predictors were significant. Step 3 added the interaction between the PCL:SV facets and history of physical abuse, F(11, 369) = 2.43, p = .006. There was a significant interaction between the antisocial facet and history of physical abuse (p = .030). Probing this association using simple slopes analysis (see Figure 2) showed that high antisocial traits predicted verbal aggression for men with physical abuse history (p = .012), but not for men without physical abuse history (p = .983).

Figure 2.

Men: The moderating effect of physical abuse on the association between antisocial psychopathic traits and verbal aggression.

Indirect Aggression

Table 3 displays the results of the hierarchical linear regression predicting indirect aggression. For women, Step 1 was significant, F(3, 204) = 3.68, p = .013, and physical abuse was significant (p = .031). Step 2 added the PCL:SV facets, F(7, 204) = 4.29, p < .001, and the interpersonal facet was significant (p = .047). Step 3 added the interaction terms, F(11, 204) = 3.37, p < .001. The interaction between physical abuse and the antisocial facet was significant (p = .036). Simple slopes analysis showed that low levels of antisocial psychopathic traits and no history of physical abuse were associated with the lowest levels of indirect aggression (see Figure 3).

Table 3.

Psychopathy and Lifetime History of Physical Abuse as Predictors of Indirect Aggression.

	Indirect Aggression: Women				Indirect Aggression: Men
	B	SE B	β	∆R²	B	SE B	β	∆R²
Step 1				.05*				.11***
Age	−0.46	0.27	−.12		−0.29	0.26	−.06
Substance Dependence	0.35	0.28	.09		1.18	0.23	.27***
Physical Abuse	1.40	0.65	.16*		1.29	0.47	.14**
Step 2				.08**				.08***
Age	−0.65	0.27	−.17*		−0.44	0.25	−.08
Substance Dependence	−0.46	0.37	−.12		−0.01	0.30	.00
Physical Abuse	1.00	0.65	.11		0.87	0.47	.09
PCL:SV Interpersonal	0.90	0.45	.17*		0.23	0.25	.05
PCL:SV Affective	0.46	0.49	.08		0.14	0.29	.03
PCL:SV Lifestyle	0.30	0.43	.07		−0.16	0.32	−.04
PCL:SV Antisocial	0.65	0.56	.13		1.60	0.36	.38***
Step 3				.03				.01
Age	−0.69	0.27	−.18*		−0.45	0.25	−.09
Substance Dependence	−0.39	0.38	−.10		0.02	0.31	.01
Physical Abuse	0.58	0.77	.06		1.03	0.51	.11*
PCL:SV Interpersonal	0.97	0.50	.19		0.20	0.31	.05
PCL:SV Affective	0.48	0.76	.09		0.27	0.37	.06
PCL:SV Lifestyle	−0.21	0.60	−.05		−0.49	0.38	−.11
PCL:SV Antisocial	1.51	0.70	.31*		1.84	0.43	.44***
Interpersonal × Physical Abuse	−0.52	1.05	−.05		0.05	0.53	.01
Affective × Physical Abuse	0.40	1.02	.05		−0.36	0.61	−.05
Lifestyle × Physical Abuse	0.53	0.88	.06		1.03	0.69	.13
Antisocial × Physical Abuse	−2.18	1.03	−.23*		−0.75	0.69	−.11

Note. PCL:SV = Psychopathy Checklist: Screening Version.

p < .05. **p < .01. ***p < .001.

Figure 3.

Women: The moderating effect of physical abuse on the association between antisocial psychopathic traits and indirect aggression.

In the male sample, Step 1 was significant, F(3, 365) = 14.40, p < .001. Substance dependence (p < .001) and physical abuse (p = .007) were significant. Step 2 added the PCL:SV facets, F(7, 365) = 11.90, p < .001, and the antisocial facet was significant (p <.001). Step 3 added the interaction between the PCL:SV facets and history of physical abuse, F(11, 365) = 7.78, p < .001. No significant interactions were found.

Discussion

Our main expectations for psychopathy were supported. First, physical aggression for men and women was predicted by the antisocial psychopathy facet, regardless of physical abuse. Thus, the antisocial facet is a sex-neutral risk factor. In contrast, the affective facet was only predictive for women. However, when considering the moderating effect of physical abuse on the affective facet, affective psychopathic traits were significant in both men and women but had very different effects. In women, high levels of physical aggression were associated with high affective psychopathic traits only in those with a lifetime history of physical abuse. Because prior research has shown that physical abuse impacts emotion regulation capabilities (Masten & Coatsworth, 1998; Teisl & Cicchetti, 2008), our finding extends support for recent evidence that women with emotion regulation problems and affective psychopathic traits pose a particular risk for violent behavior (Thomson et al., 2018).

In contrast to the findings in women, physical aggression in men was associated with affective traits in two directions. First, low affective facet scores with physical abuse history were related to higher levels of physical aggression. This is consistent with research from an adolescent sample, which found high levels of harsh and inconsistent discipline predicted antisocial behavior but only for those with low scores on the affective facet of the Psychopathy Checklist: Youth Version (Edens, Skopp, & Cahill, 2008). This may suggest that those with lower affective psychopathic traits may be more prone to become aggressive because of harsher environments (i.e., exposure to physical abuse or harsh discipline). Expectedly, lower physical aggression was predicted by the combination of low affective traits and no history of physical abuse. Thus, it seems that the presence or absence of physical abuse has a greater effect on aggression for those with low levels of affective psychopathic traits. Collectively, these results show that in men, there is a strong link between physical abuse and physical aggression, but only among those with lower levels of affective psychopathic traits, whereas in women, physical aggression is best predicted by the combination of physical abuse and high levels of affective psychopathic traits.

With regard to verbal aggression, we expected the antisocial facet would be positively associated for both men and women, as shown in prior research (Anestis et al., 2017; Colins et al., 2017). Our results show a positive association between antisocial psychopathic traits and verbal aggression but only for women. This null finding in men corresponds with a correlational study involving a sample of male psychiatric and personality disordered patients, which showed verbal aggression was not associated with any of the psychopathy facets (Zwets et al., 2015). An additional sex difference emerged when testing the interaction between the antisocial facet and physical abuse. For women, physical abuse did not moderate the antisocial facet and verbal aggression link, but it did for men. Thus, the antisocial facet increases the risk of verbal aggression in women, but the association for men seems to be contingent on physical abuse history.

The results for indirect aggression also presented sex differences. In men, the antisocial facet predicted indirect aggression, whereas in women, the interpersonal facet predicted indirect aggression. This suggests that women who are more manipulative and superficially charming engage in discrete methods of aggression. The only significant interaction to emerge was for women, and this showed low levels of indirect aggression were predicted by the combination of low scores on the antisocial facet and no history of physical abuse. These results show the importance of considering the influence of physical abuse on the psychopathy–aggression link, and testing for sex differences.

Prior research has indicated that the effects of physical abuse may disrupt or interfere with emotion regulation capability and social information processing, which places victims of physical abuse at greater risk of being the victim and perpetrator of future aggression. Indeed, in the present study, we found LPA was associated with higher levels of physical and indirect aggression in men and women but, unexpectedly, was not related to verbal aggression. This suggests that physical abuse places individuals at specific risk of causing physical harm to others, as well as harm to social relationships (e.g., spreading rumors, gossiping, and excluding the person).

Implications

The present study demonstrates the importance of considering LPA in understanding risk factors for aggression but also provides further evidence that there are notable sex differences in risk factors for aggressive behavior. Consistent with prior research including women (Thomson, Bozgunov, et al., 2019; Thomson, Vassileva, et al., 2019), higher levels of affective psychopathic traits in women predicted higher physical aggression, but this was not found in the male sample. Based on the literature to date, it seems that the antisocial facet can be considered a gender-neutral risk factor for physical aggression, while the affective facet seems to be female-specific (Thomson, Bozgunov, et al., 2019). From a treatment perspective, this suggests that some aspects of interventions may be beneficial for both men and women to reduce psychopathy-related aggression. These interventions may include a curriculum that targets poor behavioral controls and criminal thinking styles (e.g., Moral Reconation Therapy). However, these may not be suited for women with psychopathic traits.

The interpersonal-affective features of psychopathy are notoriously difficult to treat (Lewis, 2018; Thomson, 2019), therefore, the aim of treatment is to help reduce how these traits negatively impact the individual and others around them. As Sewall and Olver (2018) state, “it is not illegal to be an unpleasant person, but it is clearly illegal to commit a violent sexual assault” (p. 2). Thus, finding links between psychopathic personality traits and aggression is important to help break the link. The present study suggests that a potential mechanism for women is exposure to physical abuse. Because of sex differences in the experience and sequelae of abuse (Fisher et al., 2009; Greenfield et al., 2007; Thompson, Kingree, & Desai, 2004; Walker, Carey, Mohr, Stein, & Seedat, 2004), it is imperative that interventions be developed specifically for women with a focus of a trauma-informed approach (e.g., Beyond Violence; Covington, 2013), especially if these women have high levels of affective psychopathic traits. This finding also highlights that psychopathic women are not just perpetrators of violence; rather, they are victims of past injustices. In sum, these subtle sex differences are important for informing treatment and reducing the rates of aggression and violence.

Limitations

Although the present study provides insight into the effects of physical abuse on the association between psychopathy and aggression in men and women, there are some limitations to consider. First, our measure of physical abuse measured lifetime occurrence, which may have included abuse during childhood and/or adulthood. It is possible that physical abuse during childhood or adulthood could have different effects on both the development of psychopathy, as well as the psychopathy–aggression link. Furthermore, our measure of physical abuse was binary and, therefore, we were unable to assess the severity of physical abuse, which could have impacted the results. Thus, we look forward to seeing future research disentangling these associations. Nevertheless, the Addiction Severity Index (ASI) is a semistructured interview and a reliable measure of physical abuse occurring across the life span; thus, the findings provide an important starting point to understanding the effects of physical abuse on aggression. Next, we used a community sample of Bulgarian men and women; therefore, our findings will need to be replicated cross-culturally, as well as in environments where levels of violence, psychopathy, and histories of abuse may be more prevalent (i.e., prisons). Although we controlled for recent drug exposure by only enrolling participants with negative urine drug screens and negative breathalyzer test for alcohol, we did not have data on prenatal drug exposure or on childhood versus adult violence, which may have influenced the results. Future studies should also investigate potential effects of type of drug use. Last, our measure of aggression did not capture the subtypes of aggression (e.g., reactive or proactive). Because physical abuse is thought to impact emotion regulation, and emotion dysregulation moderates the link between psychopathy and reactive aggression (Thomson et al., 2018), it may be that physical abuse differently moderates the link between psychopathy and aggression subtypes.

Conclusion

In sum, the present findings demonstrate that both psychopathy and exposure to LPA are risk factors for physical, verbal, and indirect aggression. Our aim was to determine whether these associations and the moderating effect of physical abuse on psychopathy-related aggression were different for men and women. Overall, the results showed there are some similarities between men and women, but in line with prior research in female samples, there were notable differences concerning affective psychopathic traits. Men with a lifetime history of physical abuse who had low affective traits were more physically aggressive, whereas physically abused women with higher affective traits had higher levels of physical aggression. In contrast, women who are manipulative, deceitful, and superficially charming reported using more discrete and “behind the back” forms of aggression to damage social relationships. These differences between men and women support the need for more female-responsive interventions to target sex-specific risk factors for aggressive behavior.

Footnotes

Authors’ Note

Jasmin Vassileva is also affiliated with Virginia Commonwealth University Health, Richmond, USA.

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) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Research reported in this publication was supported by the National Institute on Drug Abuse (NIDA) and the Fogarty International Center (FIC) under award number R01DA021421 (JV).

ORCID iD

Nicholas D. Thomson

Author Biographies

Nicholas D. Thomson, PhD, is an assistant professor in the Department of Surgery at Virginia Commonwealth University Medical Center and Honorary Fellow at Durham University. His research interests include sex differences in personality disorders and violence, violence risk assessment, and injury and violence prevention.

Kiril Bozgunov, PhD, obtained his doctoral degree in psychology at Sofia University “Kliment Ohridski” in 2017. His dissertation examined the relationships between psychopathy, alexithymia, and anxiety. He is currently a project manager at the Bulgarian Addictions Institute in Sofia, Bulgaria. His main interests are in the relationship of psychopathy with other personality traits and addictive disorders, and in motivational interviewing.

Elena Psederska, MA, is a PhD student in the Department of Cognitive Science and Psychology at New Bulgarian University and a research assistant at the Bulgarian Addictions Institute in Sofia, Bulgaria. Her main research interests are related to emotional processing difficulties in individuals with substance use disorders and to various personality risk factors predisposing to drug addiction.

Michel Aboutanos, MD, MPH, is professor of surgery at Virginia Commonwealth University (VCU) Medical Center, and chief of trauma at VCU Level 1 Trauma Center, and director of the Injury and Violence Prevention Program. As a surgeon-scientist, his research interests include youth violence, and hospital-based injury and violence prevention.

Georgi Vasilev, MD, MPH, is an addiction psychiatrist and the director of the Bulgarian Addictions Institute in Sofia, Bulgaria. His research interests are focused on risk factors for addictions and on behavioral and pharmacological interventions for addictions.

Jasmin Vassileva, PhD, is a tenured associate professor of psychiatry and psychology at the Institute for Drug and Alcohol Studies at Virginia Commonwealth University. Her program of research focuses on personality and neurocognitive risk factors for drug addiction and externalizing psychopathology and neurocognitive sequelae of chronic drug use.

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