The following study examines the combined influences of alcohol use and psychopathy on aggressive behavior in the context of intimate partner violence. This is the bottom line of a recently published article in Law and Human Behavior. Below is a summary of the research and findings as well as a translation of this research into practice.
Featured Article | Law and Human Behavior | 2016, Vol. 40, No. 2, Online First Publication
Psychopathy, Alcohol Use, and Intimate Partner Violence: Evidence From Two Samples
Marisa Okano, McGill University
Jennifer Langille, University of British Columbia
Zach Walsh, University of British Columbia
Intimate partner violence (IPV) is a substantial public health problem. Psychopathic personality is one of the most important individual difference predictors of violence and has been proposed as a key feature for understanding IPV perpetration. Psychopathy is also associated with alcohol use, a prominent risk factor for IPV. This pattern of interrelationship raises the possibility that psychopathy might mediate the relationship between alcohol use and IPV. However, few studies have examined the combined influences of alcohol use and psychopathy on aggressive behavior, and, to our knowledge, no study has directly examined these interrelationships in the context of IPV. In the present study, we aim to enhance our understanding of risk for IPV perpetration by examining the consistency of the association between psychopathy and violence across levels of alcohol use and gender in 2 samples: a prospective clinical sample (n = 703) and a cross-sectional sample of university students (n = 870). Psychopathy was associated with IPV across both samples independently and, after controlling for gender and alcohol use (R2 = .04–.08), also mediated the relationship between alcohol use and IPV among the nonclinical sample. We found that psychopathy was associated with IPV, that this relationship was consistent despite gender and alcohol use, and was evident across samples. This relationship was small but robust, and appeared to be more prominent than the association between alcohol use and IPV. Future research that examines IPV risk should consider the potential role of psychopathy, particularly when investigating risk associated with alcohol use.
partner violence, psychopathy, alcohol abuse, personality, gender
Summary of the Research
“Intimate partner violence (IPV) is a substantial public health problem, as victimization is linked to physical injury, chronic pain, increased substance abuse, and numerous other health problems. A robust literature has examined the individual differences that influence risk for IPV perpetration, with substantial research focusing on alcohol use and personality features as important predictors. Indeed, alcohol use is cited among the most prominent risk factors for IPV, although evidence suggests that this association may vary according to sample type and individual differences in personality” (p. 1).
“With regard to personality, psychopathy has emerged as one of the most important individual difference predictors of violence in general, and has been proposed to be a key feature for understanding IPV perpetration. Several studies have identified an association between psychopathy and domestic violence among male forensic and clinical samples . . . Psychopathic personality features are also associated with alcohol use, which raises the possibility that psychopathic personality might mediate the relationship between alcohol use and IPV. However, few studies have examined the combined influences of alcohol use and psychopathy on aggressive behavior, and, to our knowledge, no study has directly examined this pattern of interrelationships in the context of IPV” (p. 1).
“Despite the considerable evidence showing the independent contributions of both alcohol use and psychopathic personality to IPV perpetration, relatively few studies have examined the patterns of interrelationship among these factors. Evidence from laboratory studies of aggression is equivocal. A study of young adults found that the antisocial facet of psychopathic personality potentiated the exacerbating effects of alcohol on aggressive behavior. However, a study of university students found no moderating relationship between psychopathy and alcohol-related aggression. In sum, further research is required to more definitively determine the extent to which the violence risks associated with both psychopathic personality and alcohol use are distinct, multiplicative, or redundant” (p. 2).
This research first utilized a prospective design with a clinical sample of 703 civil psychiatric patients to “examine the independent and interactive predictive effects of psychopathy and alcohol dependence for IPV perpetration” (p. 2). “Participants were followed for 12 months subsequent to discharge from an inpatient psychiatric facility, during which time they underwent thorough assessments for psychopathology, substance use, and violence every 10 weeks, providing five possible assessment opportunities” (p. 2).
In the first study, “males demonstrated higher rates of psychopathy than females. Males were also more likely than females to meet criteria for a CAD [current alcohol dependence]. Individuals with CAD demonstrated higher levels of psychopathy than did those without CAD. Scores on the PCL:SV predicted IPV, both independently and uniquely after accounting for gender and CAD. Problematic alcohol use was not related to IPV; therefore, criteria for mediation were not met. Females reported significantly higher rates of IPV perpetration than their male counterpart. Further, gender predicted IPV perpetration, such that perpetration was more likely among females. There were no significant two-way or three-way interactions” (p. 3).
“The primary aim for Study 2 was to examine the extent to which relationships identified in Study 1 generalized to a nonclinical sample. Participants were 870 undergraduate students at a Canadian university” (p. 3).
Translating Research into Practice
“This study was designed to examine the relationship between psychopathy and the perpetration of violence toward intimate partners. We found that psychopathy was associated with IPV, and that this relationship was robust across gender and alcohol use, and was evident in both clinical and nonclinical samples. The sizes of the observed effects were in the small range, which is generally consistent with prior findings regarding the predictive power of psychopathy for violence. Relationships of this magnitude are not practically trivial; among the clinical sample in this study, approximately one third of the higher psychopathy participants were arrested for IPV compared with approximately one fifth of the lower psychopathy group, and a discrepancy of a similar size was observed among the university sample. Our identification of a positive relationship between psychopathy and IPV is consistent with prior studies of psychopathy and violence among men and women” (p. 4).
“The relationship between psychopathic personality and IPV appeared to be relatively more robust than the relationship between IPV and problematic alcohol use. Whereas psychopathy was associated with IPV in both samples, problematic alcohol use was not predictive among the clinical sample, and the observed relationship between problematic alcohol use and IPV among the university sample was largely accounted for by covariance with psychopathy. We interpret this finding cautiously in light of the considerable literature that has identified alcohol as an important risk factor for IPV. Nonetheless, the extent to which the relationship between alcohol use and violence may reflect unmeasured psychopathic personality warrants further research, and our findings suggest that psychopathy should be routinely assessed in research on alcohol use and violence” (p. 4).
Other Interesting Tidbits for Researchers and Clinicians
“This study was the first to examine the consistency of the relationship between psychopathy and IPV across gender. The finding that the association between psychopathy and IPV was equivalent for males and females in both samples represents preliminary evidence for the generalizability of the predictive power of psychopathy across gender, and adds to the growing literature on the manifestations of psychopathic personality among females. This apparent symmetry has both practical and theoretical implications” (p. 4).
“From a theoretical perspective, it highlights the relevance of individual differences in personality for understanding risk of IPV perpetration among both men and women. Importantly, this should not be interpreted as diminishing the value of perspectives that foreground structural and social factors. Indeed, the substantial variance in IPV that remained unexplained in both samples highlights the need for a multisystemic approach to elucidating the complex problem of IPV. In addition, our identification of positive associations between psychopathy and IPV despite the relatively low levels of psychopathy in both samples appears to be consistent with assertions that psychopathic personality can be meaningfully characterized as a continuous trait, with meaningful variation even at the low end of the spectrum. From a practical perspective, these findings have the potential to inform risk assessment, and provide further support for the value of including psychopathic personality in actuarial tools. However, evidence of consistent prediction across gender should be considered together with research that has highlighted inconsistent predictive power of psychopathy across ethnicity and socioeconomic status” (p.4).
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