Brian M. Hicks

Etiologic Connections Among Substance Dependence, Antisocial Behavior, and Personality: Modeling the Externalizing Spectrum

A hierarchical biometric model is presented of the origins of comorbidity among substance dependence, antisocial behavior, and a disinhibited personality style. The model posits a spectrum of personality and psychopathology, united by an externalizing factor linked to each phenotype within the spectrum, as well as specific factors that account for distinctions among phenotypes within the spectrum. This model fit self-report and mother-report data from 1,048 male and female 17-year-old twins. The variance of the externalizing factor was mostly genetic, but both genetic and environmental factors accounted for distinctions among phenotypes within the spectrum. These results reconcile evidence for general and specific causal factors within the externalizing spectrum and offer the externalizing factor as a novel target for future research.

Factor Structure of the Psychopathic Personality Inventory: Validity and Implications for Clinical Assessment

Psychopathy is a personality disorder characterized by impulsive antisocial deviance in the context of emotional and interpersonal detachment. A factor analysis of the subscales of the Psychopathic Personality Inventory (PPI) yielded evidence for 2 factors. One factor showed relations with external criteria mirroring those of the emotional-interpersonal facet of psychopathy, including high dominance, low anxiety, and venturesomeness. The other factor showed relations paralleling those of the social deviance facet of psychopathy, including positive correlations with antisocial behavior and substance abuse, negative correlations with socioeconomic status and verbal ability, and personality characteristics including high negative emotionally and low behavioral constraint. Findings support using the PPI to assess these facets of psychopathy in community samples and to explore their behavioral correlates and genetic-neurobiological underpinnings.

Identifying Psychopathy Subtypes on the Basis of Personality Structure

The authors used model-based cluster analysis to identify subtypes of criminal psychopaths on the basis of differences in personality structure. Participants included 96 male prisoners diagnosed as psychopathic, using the Psychopathy Checklist Revised (PCL-R; R. D. Hare, 1991). Personality was assessed using the brief form of the Multidimensional Personality Questionnaire (MPQ-BF; C. J. Patrick, J. J. Curtin, and A. Tellegen, 2002). The best-fitting model yielded two clusters. Emotionally stable psychopaths were characterized by low Stress Reaction and high Agency. Aggressive psychopaths were characterized by high Negative Emotionality, low Constraint, and low Communion. These results suggest that psychopaths as defined by the PCL-R includes distinct subtypes, distinguishable in terms of personality structure, that may reflect different etiologies.

Estimating Facets of Psychopathy From Normal Personality Traits: A Step Toward Community Epidemiological Investigations

In three samples consisting of community and undergraduate men and women and incarcerated men, we examined the criterion validity of two distinct factors of psychopathy embodied in the Psychopathic Personality Inventory (PPI) as indexed by primary trait scales from the Multidimensional Personality Questionnaire (MPQ). Consistent with the PPI factors themselves, MPQ-estimated PPI-I related negatively with internalizing disorder symptoms and fearfulness and positively with thrill and adventure seeking, sociability, activity, and narcissism. MPQ-estimated PPI-II was associated negatively with socialization and positively with externalizing disorder symptoms, impulsivity, disinhibition and boredom susceptibility, and trait anxiety and negative emotionality. Additionally, PPI-I was selectively related to the interpersonal facet of Factor 1 of the Psychopathy Checklist—Revised (PCL-R), whereas PPI-II was related preferentially to Factor 2 of the PCL-R.

Psychopathic personality traits: heritability and genetic overlap with internalizing and externalizing psychopathology

BACKGROUND Little research has examined genetic and environmental contributions to psychopathic personality traits. Additionally, no studies have examined etiological connections between psychopathic traits and the broad psychopathological domains of internalizing (mood and anxiety) and externalizing (antisocial behavior, substance abuse). The current study was designed to fill these gaps in the literature. METHOD Participants were 626 pairs of 17-year-old male and female twins from the community. Psychopathic traits were indexed using scores on the Multidimensional Personality Questionnaire (MPQ). Symptoms of internalizing and externalizing psychopathology were obtained via structured clinical interviews. Structural equation modeling was used to estimate genetic and environmental influences on psychopathic personality traits as well as the degree of genetic overlap between these traits and composites of internalizing and externalizing. RESULTS Twin analyses revealed significant genetic influence on distinct psychopathic traits (Fearless Dominance and Impulsive Antisociality). Moreover, Fearless Dominance was associated with reduced genetic risk for internalizing psychopathology, and Impulsive Antisociality was associated with increased genetic risk for externalizing psychopathology. CONCLUSIONS These results indicate that different psychopathic traits as measured by the MPQ show distinct genetically based relations with broad dimensions of DSM psychopathology.

Altruism and Antisocial Behavior: Independent Tendencies, Unique Personality Correlates, Distinct Etiologies

The relationship between altruism and antisocial behavior has received limited attention because altruism and antisocial behavior tend to be studied and discussed in distinct literatures. Our research bridges these literatures by focusing on three fundamental questions. First, are altruism and antisocial behavior opposite ends of a single dimension, or can they coexist in the same individual? Second, do altruism and antisocial behavior have the same or distinct etiologies? Third, do they stem from the same or from distinct aspects of a persons personality? Our findings indicate that altruism and antisocial behavior are uncorrelated tendencies stemming from different sources. Whereas altruism was linked primarily to shared (i.e., familial) environments, unique (i.e., nonfamilial) environments, and personality traits reflecting positive emotionality, antisocial behavior was linked primarily to genes, unique environments, and personality traits reflecting negative emotionality and a lack of constraint.

Psychopathy and negative emotionality: Analyses of suppressor effects reveal distinct relations with emotional distress, fearfulness, and anger-hostility

Low negative emotionality (NEM) holds a central place in classic descriptions and seminal theories of psychopathy. However, the empirical link between low NEM and psychopathy is weak. The authors posited that this inconsistency is due to the multifaceted nature of both the NEM and psychopathy constructs and to suppressor effects between facets of psychopathy in relation to NEM criteria. The authors sought to delineate the differential associations between facets of psychopathy and NEM in a large sample of male prisoners using the Psychopathy Checklist--Revised (PCL-R; R. D. Hare, 2003) and self-report measures assessing different aspects of NEM. Statistical analyses revealed that the interpersonal-affective facet of psychopathy is negatively associated whereas the social deviance facet of psychopathy is positively associated with facets of NEM. The results demonstrate that suppressor effects can reconcile the centrality of NEM in classic descriptions of psychopathy with empirical investigations using the PCL-R.

Environmental Adversity and Increasing Genetic Risk for Externalizing Disorders

CONTEXT Studies of gene-environment interplay in the development of psychiatric and substance use disorders are rapidly accumulating. However, few attempts have been made to integrate findings and to articulate general mechanisms of gene-environment influence in the emergence of psychopathology. OBJECTIVE To identify patterns of gene-environment interplay between externalizing disorders (antisocial behavior and substance use) and several environmental risk factors. DESIGN We used quantitative genetic models to examine how genetic and environmental risk for externalizing disorders changes as a function of environmental context. SETTING Participants were recruited from the community and took part in a daylong assessment at a university laboratory. PARTICIPANTS The sample consisted of 1315 male and female twin pairs participating in the assessment of the Minnesota Twin Family Study at age 17 years. MAIN OUTCOME MEASURES Multiple measures and informants were used to construct a composite of externalizing disorders and composite measures of 6 environmental risk factors, including academic achievement and engagement, antisocial and prosocial peer affiliations, mother-child and father-child relationship problems, and stressful life events. RESULTS A significant gene x environment interaction was detected between each environmental risk factor and externalizing such that greater environmental adversity was associated with increased genetic risk for externalizing. CONCLUSIONS In the context of environmental adversity, genetic factors become more important in the etiology of externalizing disorders. The consistency of the results further suggests a general mechanism of environmental influence on externalizing disorders regardless of the specific form of the environmental risk.

Gender differences and developmental change in externalizing disorders from late adolescence to early adulthood: A longitudinal twin study.

Using data from over 1,000 male and female twins participating in the Minnesota Twin Family Study, the authors examined developmental change, gender differences, and genetic and environmental contributions to the symptom levels of four externalizing disorders (adult antisocial behavior, alcohol dependence, nicotine dependence, and drug dependence) from ages 17 to 24. Both men and women increased in symptoms for each externalizing disorder, with men increasing at a greater rate than women, such that a modest gender gap at age 17 widened to a large one at age 24. Additionally, a mean-level gender difference on a latent Externalizing factor could account for the mean-level gender differences for the individual disorders. Biometric analyses revealed increasing genetic variation and heritability for men but a trend toward decreasing genetic variation and increasing environmental effects for women. Results illustrate the importance of gender and developmental context for symptom expression and the utility of structural models to integrate general trends and disorder-specific characteristics.

Continuity and change in psychopathic traits as measured via normal-range personality: a longitudinal-biometric study.

The discriminant validity of the interpersonal-affective and social deviance traits of psychopathy has been well documented. However, few studies have explored whether these traits follow distinct or comparable developmental paths. The present study used the Multidimensional Personality Questionnaire (A. Tellegen, in press) to examine the development of the psychopathic traits of Fearless Dominance (i.e., interpersonal-affective) and Impulsive Antisociality (i.e., social deviance) from late adolescence to early adulthood in a longitudinal-epidemiological sample of male and female twins. Results from mean- and individual-level analyses revealed stability in Fearless Dominance from late adolescence to early adulthood, whereas Impulsive Antisociality declined over this developmental period. In addition, biometric findings indicated greater genetic contributions to stability in these traits and greater nonshared environmental contributions to their change over time. Collectively, these findings suggest distinct developmental trends for psychopathic traits from late adolescence to early adulthood.