A Systematic Review of the Biological Correlates and Consequences of Childhood Maltreatment and Adverse Childhood Experiences.

Childhood maltreatment (CM) and adverse childhood experiences (ACEs) are two primary forms of interpersonal victimization that have been associated with a host of deleterious health outcomes. Studies over the past decade have begun to use a range of biologically informed methods to better understand the role biology plays in the relationship between CM, ACEs, and later life outcomes. This line of research has shown that both forms of victimization occur at sensitive periods of development, which can increase the likelihood of "getting under the skin" and influence health and behavior across the life course. This review examines the current state of knowledge on this hypothesis. One hundred and ninety-nine studies are included in this systematic review based on criteria that they be written in English, use a biologically informed method, and be conducted on samples of humans. Results reveal that latent additive genetic influences, biological system functioning captured by biomarkers, polygenic risk scores, and neurobiological factors are commonly associated with exposure and response to CM and ACEs. The implication of these findings for the existing body of research on early life victimization and recommendations for future research and policy are discussed.

The Immigrant Experience and Alcohol Use: Heart Rate as a Source of Risk and Resilience.

The immigration experience in the USA has been linked to a wide range of behavioral and physical outcomes. Studies report that immigrants, relative to native-born citizens, are less likely to develop alcohol use habits despite facing hardship during the acculturation process. Limited research, however, has examined whether and to what extent resting heart rate (RHR) plays a role in accounting for individual differences in the acculturation process in the USA. To begin to address this gap in research, cross-sectional self-report data (N = 4775) from a nationally representative sample of US adults are analyzed to examine the association between the immigrant experience, alcohol use, and drunkenness. The role of low, mean, and high RHR on this association is investigated. The results reveal that respondents with higher levels of the immigrant experience report lower levels of alcohol use and drunkenness. RHR partially conditions the relationship between the immigrant experience and alcohol use, whereby respondents with higher levels of the immigrant experience and high RHR report less alcohol use and drunkenness, compared to more native respondents with low RHR. Immigrant experience and alcohol use were associated, but not with drunkenness among respondents with average RHR levels, relative to those with low RHR levels. The results suggest that RHR may be a potential source of both risk for and resilience to the development of alcohol use behaviors among immigrants going through the acculturation process in the USA.

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.

Testing the role of inflammation in the relation of childhood maltreatment and suicidal ideation among young adults.

BACKGROUND: In recent years, the prevalence of suicidal ideation among young adults has been on the rise, with childhood maltreatment thought to partially explain this disparity. Systemic inflammation-a product of over-activation of the body's stress response system-has been hypothesized to play a predictive role in the development of suicidal ideation. Enduring childhood maltreatment can lead to systemic inflammation, possibly accounting for suicidal ideation's increased prevalence among young adults who have a history of childhood maltreatment. METHODS: The current study sought to investigate the importance of childhood maltreatment as a static risk factor for downstream suicidal ideation in young adulthood with the immunological response (i.e., systemic inflammation) to childhood maltreatment serving as a mediating factor. RESULTS: Systemic inflammation was found to be positively associated with suicidal ideation, supporting the unique role systemic inflammation may play in the pathogenesis of suicidal ideation, though hypotheses regarding childhood maltreatment were not supported. CONCLUSION: This study provides novel insight into a potential immunobiological model for suicidal ideation development in young adult populations.

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.

Inflammatory and environmental contributions to social information processing.

It appears that social information processing is negatively affected by inflammation, but extant research is primarily experimental and comes from laboratory-based manipulations of inflammatory states. We aimed to examine interactions between inflammation, stressful life events, and positive memories of childhood relations with parents in relation to social information processing in 201 adults. We hypothesized that increased inflammation and stressful life events would be associated with greater hostile social information processing, but that positive memories of childhood relations with parents would moderate both relations. Results indicated that high IL-6 levels and stressful life events were significantly associated with direct and hostile social information processing. Positive memories of childhood relations with parents attenuated the link between stressful life events and social information processing. Findings suggest that both immune function and environmental stressors are related to social information processing and that positive memories of childhood relations exert some buffering effect.

An exploratory analysis of testosterone, cortisol, and aggressive behavior type in men and women.

Increasing evidence indicates that the interaction between testosterone and cortisol is associated with variation in aggressive behavior. However, results are mixed. The current study further explored the association between testosterone, cortisol, and both reactive and proactive aggression in a large sample of university students. Models considered direct and interactive effects between baseline measures of testosterone and cortisol as well as change in hormones in response to a social stressor. In women, baseline cortisol had a negative direct association with reactive aggression and was further associated with reactive aggression in interaction with baseline testosterone (positive interaction). Hormones were unrelated to reactive aggression in men. Baseline cortisol had a negative direct association with proactive aggression in women. In contrast, the association between change in cortisol and proactive aggression was positive. Cortisol was not associated with proactive aggression in men. In addition, testosterone was not related to proactive aggression either directly or in interaction with cortisol in either men or women. Collectively, these results show that the association between hormones and aggression varies across aggressive behavior type and across sex.

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.

Low Resting Heart Rate and Stalking Perpetration.

There is consistent evidence to suggest that individuals with low resting heart rate are more likely to engage in a variety of antisocial behaviors. The present study examines whether this finding can be extended to stalking perpetration. Drawing from fearlessness theory and stimulation-seeking theory, as well as conceptual work of Meloy and Fisher, we find that individuals with low resting heart rates had significantly greater odds of engaging in stalking behavior, net of controls for sex, age, race, self-control, parental affection, delinquent peers, attitudes/beliefs toward crime, and aggression. When disaggregated by sex, the heart rate-stalking relationship was found to be significant for males, but not for females. The implications of these findings are discussed from a biosocial perspective.

Skin conductance, heart rate and aggressive behavior type.

The current study tested the association between physiology and aggressive behavior type in a large sample of University students (N = 509). Measures of aggression were gathered with the Reactive and Proactive Aggression Questionnaire. Analyses used raw aggressive behavior type scores and residualized measures of aggressive behavior type, which account for the overlap between reactive and proactive aggression. Measures of physiology included skin conductance and heart rate, both at rest and in response to a minor social stressor. Analyses assessed the association between aggressive behavior type and measures of physiology in the full sample and in sex specific sub-samples. Results indicated that resting skin conductance was positively associated with proactive aggression in the full sample and among females. Skin conductance in response to stress had a positive association with reactive aggression both in the full sample and among males. Skin conductance responsivity was negatively associated with proactive aggression among males. Findings further strengthen previous work suggesting that the etiologies of reactive and proactive aggression are distinct and may vary across sex.

The relationship between the MAOA-uVNTR polymorphism, delinquent peer affiliation, and antisocial behavior with a consideration of sex differences.

With the advent of new and more readily usable gene sequencing techniques, researchers have been able to examine the interactions between genes and the environment (G X E) within a multitude of scientific perspectives. One area that G X E interactions have been implicated in is the development of antisocial behavior (ASB). Antisocial behavior consists of a wide range of maladaptive behaviors and has been at the forefront of public health and mental health concerns for decades. One genetic polymorphism that has been associated with ASB is MAOA-uVNTR. Meta-analytic studies have found the low-activity MAOA-uVNTR polymorphism to be associated with ASB from early childhood through adulthood. Recently, studies have begun to examine the independent and interactive G X E relationship between MAOA-uVNTR and deviant peer affiliation on ASB. Inconsistent with the broader literature, these findings suggest an interaction between high-activity MAOA-uVNTR and deviant peer affiliation on ASB in a mixed sex sample. The current study re-examines the relationship between MAOA-uVNTR, peer delinquency, and ASB with a consideration of sex differences in 291 college participants. Findings indicate an interaction between the low-activity allele of the MAOA-uVNTR and peer delinquency in predicting ASB. Results are also specific to differences between the sexes. Implications and future research are discussed.

A Systematic Review of Gay, Lesbian, and Bisexual Research Samples in Couple and Family Therapy Journals.

The purpose of this study is to review samples from research on gay, lesbian, and bisexual (GLB) issues and to evaluate the suitability of this body of research to support affirmative and evidence-based practice with GLB clients. The authors systematically reviewed the sampling methodology and sample composition of GLB-related research. All original, quantitative articles focusing on GLB issues published in couple and family therapy (CFT)-related journals since 1975 were coded (n = 153). Results suggest that within the GLB literature base there is some evidence of heterocentrism as well as neglect of issues of class, race, and gender. Suggestions to improve the diversity and representativeness of samples-and, thus, clinical implications-of GLB-related research in CFT literature are provided.

Sex Differences in Sources of Resilience and Vulnerability to Risk for Delinquency.

Research on adolescent risk factors for delinquency has suggested that, due to genetic differences, youth may respond differently to risk factors, with some youth displaying resilience and others a heightened vulnerability. Using a behavioral genetic design and data from the National Longitudinal Study of Adolescent to Adult Health, this study examines whether there are sex differences in the genetic and environmental factors that influence the ways in which adolescents respond to cumulative risk for violent, nonviolent, and overall delinquency in a sample of twins (152 MZ male, 155 MZ female, 140 DZ male, 130 DZ female, and 204 DZ opposite-sex twin pairs). The results revealed that males tended to show greater vulnerability to risk for all types of delinquency, and females exhibited greater resilience. Among males, additive genetic factors accounted for 41, 29, and 43 % of the variance in responses to risk for violent, nonviolent, and overall delinquency, respectively. The remaining proportion of variance in each model was attributed to unique environmental influences, with the exception of 11 % of the variance in nonviolent responses to risk being attributed to common environmental factors. Among females, no significant genetic influences were observed; however, common environmental contributions to differences in the ways females respond to risk for violent, nonviolent, and overall delinquency were 44, 42, and 45 %, respectively. The remaining variance was attributed to unique environmental influences. Overall, genetic factors moderately influenced males' responses to risk while environmental factors fully explain variation in females' responses to risk. The implications of these findings are discussed in the context of improving the understanding of relationships between risks and outcomes, as well as informing policy and practice with adolescent offenders.

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.

A longitudinal analysis of the effects of a DRD4 polymorphism on marijuana use.

The current study used a variable- and person-centered approach to examine whether a DRD4 polymorphism explained within-individual differences in frequency of marijuana use from adolescence into emerging adulthood. Data were analyzed from 1897 respondents from the genetic subsample of the National Longitudinal Study of Adolescent Health (Add Health) at waves I (ages 13-17), II (ages 14-18), and III (ages 21-25). Latent class growth model results revealed that marijuana use was characterized by four trajectories (non-users/experimenters, increasers, desisters, and chronic users), and that the DRD4 polymorphism differentiated increasers from non-users/experimenters. Overall, the results suggested that the DRD4 polymorphism may be relevant to differences in the developmental trajectories of marijuana use.

Genetic and environmental contributions to the relationship between violent victimization and criminal behavior.

Studies have shown that there is a significant association between violent victimization and criminal behavior. One potential explanation for this association is that genetically mediated processes contribute to both violent victimization and criminal behavior. The current study uses data from the twin sample of the National Longitudinal Study of Adolescent Health (n = 2,568) to examine whether genetic and/or environmental factors explain the correlation between violent victimization and criminal behavior in adolescence and early adulthood. Results from the bivariate genetic analyses reveal that genetic factors explain 39% of the covariance between violent victimization and delinquency in adolescence and 20% of the correlation between violent victimization and criminal behavior in early adulthood. The remaining covariance between violent victimization and criminal behaviors is attributed to the same nonshared environmental factors operating on both. The implications of these findings in relation to the victimization literature are discussed.

Gender, genetic risk, and criminal behavior.

The threshold hypothesis asserts that the prevalence of offending is lower among females because females have a higher threshold for risk than males. As a result, females who do offend should exhibit greater concentrations of genetic and environmental risk than male offenders. In light of these statements, the current study examines the role of genetic factors in the etiology of female offending using data from the National Longitudinal Study of Adolescent Health. The results reveal that the genetic risk threshold is higher for females than for males. However, contrary to the threshold hypothesis, female offenders exhibit fewer genetic risks than male offenders.

An interaction between DAT1 and having an alcoholic father predicts serious alcohol problems in a sample of males.

The current study examines whether the dopamine transporter (DAT1) VNTR polymorphism and paternal alcoholism are related to serious alcohol problems. Using data from the National Longitudinal Study of Adolescent Health (Add Health), we found that the DAT1 polymorphism interacted with paternal alcoholism to predict serious alcohol problems among males. Specifically, the 10-repeat allele conferred an increase of alcohol problems only among males who also had an alcoholic father; the 10-repeat allele was unrelated to alcohol problems for males without an alcoholic father. Coefficient tests revealed that this interaction effect was stronger among African-American males. Females who possessed the 9-repeat allele were more likely to report serious alcohol problems, but this effect was not moderated by paternal alcoholism. These analyses suggest that additive and interactive effects of DAT1 and paternal alcoholism may operate differently across genders and races.

The interaction of DRD2 and violent victimization on depression: an analysis by gender and race.

BACKGROUND: Recent research has shown that a polymorphism in the dopamine D2 receptor gene (DRD2) moderates the association between stressful life events and depression. The present study builds off this literature and examines whether DRD2 moderates the effect of violent victimization on depression. Furthermore, the current analyses investigate whether the effects of DRD2 and violent victimization vary by gender and by race for females. METHODS: Respondents from waves II and III of the National Longitudinal Study of Adolescent Health (Add Health) completed questionnaires regarding their depressive symptoms and violent victimization experiences (n = 2380). RESULTS: Multivariate regression results reveal that violent victimization has a strong independent effect on depressive symptoms for Caucasian females. In contrast, violent victimization is only associated with higher levels of depressive symptoms among African American females when they carry at least one A1 allele of DRD2. Results also show that DRD2 has a significant independent effect on depressive symptoms for males and African American females. CONCLUSIONS: The results suggest that African American females who carry the A1 allele of DRD2 may be more vulnerable to the negative effects of violent victimization than African American females who do not carry at least one copy of the A1 allele. LIMITATIONS: The current study's findings may not generalize to clinical populations, adults, and individuals residing in other countries. In addition, the effects of DRD2 may reflect other polymorphisms that are in linkage with DRD2.