The association between the 2D:4D ratio and psychopathic characteristics.

Prior research has identified relations between prenatal testosterone exposure and various antisocial and criminal behaviors. However, less is known about the association between prenatal testosterone exposure and personality traits, such as psychopathy. This study used self-report and biometric data from a sample of undergraduates (n = 491) at a large southwestern university to examine the association between prenatal testosterone exposure (measured by the 2D:4D ratio) and three dimensions of psychopathy (i.e., callousness, egocentricity, and antisocial behavior). Analyses were stratified by sex to explore sex-specific biological underpinnings of psychopathy in young adulthood. Results showed that males scored significantly higher in psychopathic traits and reported significantly lower 2D:4D ratios, compared to females. Additionally, 2D:4D ratios were negatively associated with egocentricity in males, but not females. These findings contribute to a growing literature on the organizational effects that prenatal testosterone exposure may have on the development of different dimensions of psychopathy.

Testosterone, cortisol, and criminal behavior in men and women.

Only two studies to date have considered the joint effects of testosterone and cortisol on direct measures of criminal behavior. The current study extends this earlier work by incorporating the direct and interactive effects of baseline hormone measures and hormone change scores in response to social stress. The current study also extends prior work by considering distinct measures of different criminal behavior types and sex differences. Analyses based on a large sample of undergraduates indicated that testosterone had a positive and statistically significant association with impulsive and violent criminal behavior. The interaction of testosterone with cortisol had a negative association with income generating crime. Simple slopes analyses of this interaction indicated testosterone had a positive association with income generating crime when cortisol was low (-1 SD). Associations between hormones and criminal behavior were not moderated by sex.

Examining the Relationship Between Victimization, Psychopathy, and the Acceptance of Rape Myths.

Rape myths are attitudes that implicitly and explicitly blame victims for their own sexual victimization. Greater adherence to rape myths is linked to several negative outcomes, including the neutralization of gender-based violence and the perpetration of sexual violence. Few studies have considered how previous life experiences and individual-level traits influence the development and greater adherence to rape myths. The current study examines how traits associated with the three-factor model of psychopathy (i.e., egocentric, callous, and antisocial dimensions) and adherence to traditional gender roles mediate the relationship between prior childhood/adolescent victimization and the acceptance of rape myths in a sample of college men and women (N = 789). Path modeling indicates that experiences of psychological victimization (before age 16) increased egocentric psychopathic traits, which then increased the acceptance of rape myths in men. In women, however, sexual victimization (before age 16) increased the acceptance of traditional gender roles, which then influenced the acceptance of rape myths. Additionally, the egocentric facet of psychopathy exerted indirect effects on the acceptance of rape myths through traditional views on gender roles in both men and women. These findings highlight the need to continue to examine egocentric personality traits in relation to the development of rape myths in adolescent and young adult populations. Directions for collegiate programming are discussed.

Further Evaluation of the Associations Between Psychopathic Traits and Symptoms of PTSD and Depression in a Nonclinical Sample.

Examining psychopathic traits at the factor or facet level has revealed that various aspects of psychopathy may be differentially related, even in opposing directions, to important outcomes (e.g., intelligence, emotion regulation). Empirical work on relations between psychopathy and internalizing disorders, such as posttraumatic stress disorder (PTSD) and depression, has provided evidence for a positive association with antisocial traits. However, findings for the affective domain have been more equivocal. The current study (N = 732) sought to replicate past findings of the positive association of antisocial psychopathic traits with higher levels of PTSD and depressive symptoms, and to further explore associations between affective traits of psychopathy and these disorders using two measures of psychopathy. Results confirmed prior findings of a positive correlation between antisocial features and self-reported PTSD/Depression symptom severity, but they did not provide evidence for any association with affective traits. Future research using longitudinal designs is needed to begin establishing temporal ordering of the psychopathy-internalizing relationship.

Monoamine oxidase A genotype, childhood adversity, and criminal behavior in an incarcerated sample.

BACKGROUND: A number of studies have found a functional variable number tandem repeat polymorphism in the upstream regulatory region of the monoamine oxidase A gene (MAOA-uVNTR) interacts with childhood adversity to increase risk for antisocial behavior. Several studies have also reported null findings. METHODS: Here, we examine the association between MAOA-uVNTR genotype, childhood adversity, and criminal activity in a sample of 99 male volunteers who were incarcerated in a large city jail in the Southern United States. MAOA-uVNTR genotypes were obtained from DNA extracted from buccal swabs. Criminal activity in the year before incarceration and childhood adversity were measured with self-report surveys. Violent arrest rates and property arrest rates were quantified with official records of arrest and accounted for periods of incarceration in local and state correctional facilities. RESULTS: The low expressing allele of the MAOA-uVNTR genotype (MAOAL) interacted with abuse to predict self-reports of less serious criminal and delinquent behavior and had a direct association with serious criminal activity. MAOAL genotype interacted with parental criminality to predict self-reports of serious criminal behavior, property arrest rates, and violent arrest rates. CONCLUSION: The findings suggest that crime prevention efforts may be improved through attention to the neurodevelopmental consequence of gene-by-environment interactions.

The role of gene-gene interaction in the prediction of criminal behavior.

A host of research has examined the possibility that environmental risk factors might condition the influence of genes on various outcomes. Less research, however, has been aimed at exploring the possibility that genetic factors might interact to impact the emergence of human traits. Even fewer studies exist examining the interaction of genes in the prediction of behavioral outcomes. The current study expands this body of research by testing the interaction between genes involved in neural transmission. Our findings suggest that certain dopamine genes interact to increase the odds of criminogenic outcomes in a national sample of Americans.