Genetic-environmental interaction in the genesis of aggressivity and conduct disorders

Parenting in the Context of the Child: Genetic and Social Processes

The focus on the role of parenting in child development has a long-standing history. When measures of parenting precede changes in child development, researchers typically infer a causal role of parenting practices and attitudes on child development. However, this research is usually conducted with parents raising their own biological offspring. Such research designs cannot account for the effects of genes that are common to parents and children, nor for genetically influenced traits in children that influence how they are parented and how parenting affects them. The aim of this monograph is to provide a clearer view of parenting by synthesizing findings from the Early Growth and Development Study (EGDS). EGDS is a longitudinal study of adopted children, their birth parents, and their rearing parents studied across infancy and childhood. Families (N = 561) were recruited in the United States through adoption agencies between 2000 and 2010. Data collection began when adoptees were 9 months old (males = 57.2%; White 54.5%, Black 13.2%, Hispanic/Latinx 13.4%, Multiracial 17.8%, other 1.1%). The median child age at adoption placement was 2 days (M = 5.58, SD = 11.32). Adoptive parents were predominantly in their 30s, White, and coming from upper-middle- or upper-class backgrounds with high educational attainment (a mode at 4-year college or graduate degree). Most adoptive parents were heterosexual couples, and were married at the beginning of the project. The birth parent sample was more racially and ethnically diverse, but the majority (70%) were White. At the beginning of the study, most birth mothers and fathers were in their 20s, with a mode of educational attainment at high school degree, and few of them were married. We have been following these family members over time, assessing their genetic influences, prenatal environment, rearing environment, and child development. Controlling for effects of genes common to parents and children, we confirmed some previously reported associations between parenting, parent psychopathology, and marital adjustment in relation to child problematic and prosocial behavior. We also observed effects of children's heritable characteristics, characteristics thought to be transmitted from parent to child by genetic means, on their parents and how those effects contributed to subsequent child development. For example, we found that genetically influenced child impulsivity and social withdrawal both elicited harsh parenting, whereas a genetically influenced sunny disposition elicited parental warmth. We found numerous instances of children's genetically influenced characteristics that enhanced positive parental influences on child development or that protected them from harsh parenting. Integrating our findings, we propose a new, genetically informed process model of parenting. We posit that parents implicitly or explicitly detect genetically influenced liabilities and assets in their children. We also suggest future research into factors such as marital adjustment, that favor parents responding with appropriate protection or enhancement. Our findings illustrate a productive use of genetic information in prevention research: helping parents respond effectively to a profile of child strengths and challenges rather than using genetic information simply to identify some children unresponsive to current preventive interventions.

Utilising Genetically-Informed Research Designs to Better Understand Family Processes and Child Development: Implications for Adoption and Foster Care Focused Interventions

Understanding the interplay between genetic factors and family environmental processes (e.g., inter-parental relationship quality, positive versus negative parenting practices) and children's mental health (e.g., anxiety, depression, conduct problems, ADHD) in the contexts of adoption and foster-care research and practice is critical for effective prevention and intervention programme development. Whilst evidence highlights the importance of family environmental processes for the mental health and well-being of children in adoption and foster care, there is relatively limited evidence of effective interventions specifically for these families. Additionally, family-based interventions not specific to the context of adoption and foster-care typically show small to medium effects, and even where interventions are efficacious, not all children benefit. One explanation for why interventions may not work well for some is that responses to intervention may be influenced by an individual's genetic make-up. This paper summarises how genetically-informed research designs can help disentangle genetic from environmental processes underlying psychopathology outcomes for children, and how this evidence can provide improved insights into the development of more effective preventative intervention targets for adoption and foster-care families. We discuss current difficulties in translating behavioural genetics research to prevention science, and provide recommendations to bridge the gap between behavioural genetics research and prevention science, with lessons for adoption and foster-care research and practice.

Parental divorce is associated with an increased risk to develop mental disorders in women

BACKGROUND

Parental divorce has been associated with reduced well-being in young adults. It is, however, unclear whether this finding is clinically relevant as studies using structured clinical interviews are missing. This study, therefore, investigated if young adults with divorced parents are at risk to develop mental disorders. Furthermore, differences in parental care, social connectedness, chronic stress and traumatic experiences between children of divorced and non-divorced parents were investigated.

METHODS

121 women (mean age: 23 years) were interviewed using the Structured Clinical Interview for DSM-IV Axis I (i.e., major mental disorders) and II (i.e., personality disorders) Disorders and asked to complete questionnaires assessing parental care, social connectedness (loneliness, attachment anxiety and avoidance), chronic stress, childhood trauma and depression.

RESULTS

Young adults of divorced parents had a higher risk for Axis I but not Axis II disorders as compared to young adults of non-divorced parents. Participants from divorced families as compared to non-divorced families reported more depression, loneliness, childhood trauma, attachment avoidance, attachment anxiety, chronic stress and less paterntal care.

LIMITATIONS

Due to the cross-sectional design of this study, conclusions about causality remain speculative.

CONCLUSION

The increased vulnerability of children of divorced parents to develop mental disorders, and to experience more chronic stress, loneliness, attachment avoidance, attachment anxiety, and traumatic experiences during childhood is alarming and highlights the importance of prevention programs and psycho-education during the process of parental divorce. Parental support with regard to adequate caregiving is needed to help parents to better support their children during and after their divorce.

Conduct Disorder-Related Hospitalization and Substance Use Disorders in American Teens

Objective: Our study aimed to compare the demographic characteristics of conduct disorder (CD) inpatients versus other psychiatric inpatients in children and adolescents, and assess the association between conduct disorder patients and the spectrum of substance use disorders (SUD). Methods: We included 800,614 psychiatric adolescent (12–18 years) inpatients, and this included 8885 inpatients (1.1%) primarily for conduct disorder in the Nationwide Inpatient Sample (2010–2014). ICD-9 codes were used to detect SUD, and a logistic regression model was used to evaluate the odds ratio (OR) for SUD in conduct disorder inpatients. Results: A higher proportion of conduct disorder inpatients were of 12–15 years of age (62.6%), male (64.4%), and White (45.7%). The lower median household income was correlated with a higher prevalence of conduct disorder (36.4%). Among SUD, cannabis use (23.7%) was most prevalent in conduct disorder inpatients followed by tobacco and alcohol use (10.1% each). Conduct disorder inpatients have 1.7-fold higher odds (95% confidence interval (CI) 1.52–1.82) for alcohol use and 1.4-fold higher odds (95% CI 1.31–1.49) for cannabis use compared to the non-conduct disorder inpatients. Cannabis use was seen significantly in adolescents (49.1%, 12–15 years), male (75.6%), and African Americans (45.6%). Conclusion: Conduct disorder inpatients have a higher risk of comorbid SUD compared to other psychiatric illnesses. The most common substance to be abused is cannabis followed by tobacco and alcohol. Varying pattern of substance use was seen by demographics and these predictors may help the clinicians for early diagnosis and treatment to improve overall health-related quality of life.

The mind-brain gap and the neuroscience-psychiatry gap

A problem underlying the mind brain gap is the complex integration among the disciplines involved in it: neurosciences, clinical psychiatry and psychology, and philosophy of science. Research in neurosciences and clinical psychiatry requires a positioning in relation to some conceptual/philosophical aspects. These are related to the models of interrelationship of the brain and the mind, to explanatory approaches in psychiatry, and to conceptual issues such as dimensionality versus categories, symptoms versus disorders, and neurobiological correlates versus clinical determination of mental disorder. In this article, we try to address some of these issues that, if taken into account, could reduce the gap between psychiatrists and neuroscientists and turn the research in this area more profitable.

Explaining suicide attempt with personality traits of aggression and impulsivity in a high risk tribal population of India

INTRODUCTION

Suicide is a spectrum of behavior including suicide ideation and suicidal attempt and is undoubtedly the outcome of the interaction of several factors. The role of two main constructs of human nature, aggression and impulsivity, has been discussed broadly in relation to suicide, as endophenotypes or traits of personality, in research and in clinical practice across diagnoses. The objective of our study was to assess impulsive and aggressive behaviors among primitive people of the Idu Mishmi tribe, who are known for high suicide completer and attempter rates.

METHODS

The study group was comprised of 177 unrelated Idu Mishmi participants divided into two sets: 39 suicide attempters and 138 non-attempters. Data on demographic factors and details of suicide attempts were collected. Participants completed a set of instruments for assessment of aggression and impulsivity traits.

RESULTS

In the Idu Mishimi population we screened (n = 177), 22.03% of the individuals had attempted suicide, a high percentage. The suicide attempters also showed a significant sex difference: 35.9% were male and 64.10% were female (p = .002*). The suicide attempters (A) scored significantly higher than non-attempters (NA) on aggression (A = 23.93,NA = 18.46) and impulsivity (A = 75.53,NA = 71.59, with p value = 0.05). The trait impulsiveness showed a significantly higher difference (F (1, 117) = 7.274) in comparison to aggression (F (1, 117) = 2.647), suggesting a profound role of impulsiveness in suicide attempts in the Idu Mishmi population. Analysis of sub-traits of aggression and impulsivity revealed significant correlations between them. Using different models, multivariate logistic regression implied roles of gender (OR = 1.079 (0.05)) and impulsiveness (OR = 3.355 (0.013)) in suicide attempts.

CONCLUSION

Results demonstrate that gender and impulsivity are strong risk factors for suicide attempts in the Idu Mishmi population.

Antisocial personality disorder: new directions

Antisocial personality disorder is a complex condition carrying high rates of comorbidity and mortality for individuals as well as harmful consequences for their families and society. Despite the publication of National Institute for Health and Care Excellence (NICE) guidelines for the disorder, the evidence base and provision of effective treatments remain inadequate, and the belief that the condition is untreatable remains widespread among psychiatrists and other professionals. This article highlights current diagnostic controversies and summarises the evidence for conceptualising antisocial personality disorder as a disorder of attachment. Informed by this developmental perspective, we provide a framework for the management and treatment of adults with antisocial personality disorder, highlighting the importance of creating a safe setting and recommending adaptations of therapeutic technique to facilitate the engagement of this ‘treatment-rejecting’ patient population. We conclude with an outline of the current government policy on the treatment of high-risk offenders with personality disorder.

LEARNING OBJECTIVES

Naturalistic Experimental Designs as Tools for Understanding the Role of Genes and the Environment in Prevention Research

Before genetic approaches were applied in experimental studies with human populations, they were used by animal and plant breeders to observe, and experimentally manipulate, the role of genes and environment on specific phenotypic or behavioral outcomes. For obvious ethical reasons, the same level of experimental control is not possible in human populations. Nonetheless, there are natural experimental designs in human populations that can serve as logical extensions of the rigorous quantitative genetic experimental designs used by animal and plant researchers. Applying concepts such as cross-fostering and common garden rearing approaches from the life science discipline, we describe human designs that can serve as naturalistic proxies for the controlled quantitative genetic experiments facilitated in life sciences research. We present the prevention relevance of three such human designs: (1) children adopted at birth by parents to whom they are not genetically related (common garden approach); (2) sibling designs where one sibling is reared from birth with unrelated adoptive parents and the other sibling is reared from birth by the biological mother of the sibling pair (cross-fostering approach); and (3) in vitro fertilization designs, including egg donation, sperm donation, embryo donation, and surrogacy (prenatal cross-fostering approach). Each of these designs allows for differentiation of the effects of the prenatal and/or postnatal rearing environment from effects of genes shared between parent and child in naturalistic ways that can inform prevention efforts. Example findings from each design type are provided and conclusions drawn about the relevance of naturalistic genetic designs to prevention science.

An analysis of genetic association in opioid dependence susceptibility

WHAT IS KNOWN

Drug addiction is a novelty-seeking personality trait that is associated with the candidate genes OPRD1 (opioid delta receptors), OPRK1 (opioid kappa receptors) and PDYN (prodynorphin). However, associations between single nucleotide polymorphisms (SNPs) rs1042114 (80G>T) of the OPRD1 gene, rs702764 (843 A>G) of the OPRK1 gene, and rs910080 (3' UTR _743T>C), rs1997794 (5' UTR -381A>G) and rs1022563 (3' UTR) of the PDYN gene and novelty seeking remain controversial as reported results have not been reproducible.

OBJECTIVE

The goal of this study was to determine the frequencies of SNPs rs1042114, rs702764, rs1997794, rs1022563 and rs910080 in the Malaysian population and to study their association with opioid dependence in Malaysian Malays.

METHODS

A total of 459 Malay male with opioid dependence and 543 healthy male (controls) subjects were included in this study. SNPs were genotyped using the TaqMan SNP genotyping assay. Statistical analysis was performed using Golden Helix SVS software suite to identify the distribution of allele and genotype frequencies, and SNP-SNP interactions were also analysed in this study.

RESULTS AND DISCUSSION

SNP rs1042114 in the OPRD1 gene is strongly associated with opiate addiction (P=.0001). In individuals homozygous for this risk allele, the likelihood of opiate addiction is increased by a factor 1.62 (95% confidence interval (CI) 1.412-1.875). Polymorphic alleles at SNP rs702764 of OPRK1 were not associated with opioid dependence. A significant association between opioid dependence and SNP rs910080 of PDYN (P=.0217) was detected, but there was no association for SNPs rs199774 and rs1022563. A significant interaction was also identified between homozygous wild-type genotype TT of rs702764 with the risk genotypes TG/GG of rs1042114 (odds ratio (OR)=2.111 (95% CI 1.227-3.631), P=.0069) and with the risk genotypes GA/AA of rs910080 (OR=1.415 (95% CI 1.04-1.912), P=.0239).

WHAT IS NEW AND CONCLUSION

The results indicate that SNPs rs1042114 and rs910080 contribute to vulnerability to opioid dependence in the Malaysian Malay population. These results will help us to understand the effect of the SNPs and the SNP-SNP interaction on opioid dependence and may assist in efforts to screen vulnerable individuals and match them with individually tailored prevention and treatment strategies.

EARLY CHILDHOOD PREDICTORS OF LOW-INCOME BOYS' PATHWAYS TO ANTISOCIAL BEHAVIOR IN CHILDHOOD, ADOLESCENCE, AND EARLY ADULTHOOD

Guided by a bridging model of pathways leading to low-income boys' early starting and persistent trajectories of antisocial behavior, the current article reviews evidence supporting the model from early childhood through early adulthood. Using primarily a cohort of 310 low-income boys of families recruited from Women, Infants, and Children Nutrition Supplement centers in a large metropolitan area followed from infancy to early adulthood and a smaller cohort of boys and girls followed through early childhood, we provide evidence supporting the critical role of parenting, maternal depression, and other proximal family risk factors in early childhood that are prospectively linked to trajectories of parent-reported conduct problems in early and middle childhood, youth-reported antisocial behavior during adolescence and early adulthood, and court-reported violent offending in adolescence. The findings are discussed in terms of the need to identify at-risk boys in early childhood and methods and platforms for engaging families in healthcare settings not previously used to implement preventive mental health services.

Exploring genetic moderators and epigenetic mediators of contextual and family effects: From Gene × Environment to epigenetics

In the current manuscript, we provide an overview of a research program at the University of Georgia's Center for Family Research designed to expand upon rapid and ongoing developments in the fields of genetics and epigenetics. By placing those developments in the context of translational research on family and community determinants of health and well-being among rural African Americans, we hope to identify novel, modifiable environments and biological processes. In the first section of the article, we review our earlier work on genotypic variation effects on the association between family context and mental and physical health outcomes as well as differential responses to family-based intervention. We then transition to discuss our more recent research on the association of family and community environments with epigenetic processes. In this second section of the article, we begin by briefly reviewing terminology and basic considerations before describing evidence that early environments may influence epigenetic motifs that potentially serve as mediators of long-term effects of early family and community environments on longer term health outcomes. We also provide evidence that genotype may sometimes influence epigenetic outcomes. Finally, we describe our recent efforts to use genome-wide characterization of epigenetic patterns to better understand the biological impact of protective parenting on long-term shifts in inflammatory processes and its potential implications for young adult health. As will be clear, research on epigenetics as a mediator of the connections between family/community processes and a range of health outcomes is still in its infancy, but the potential to develop important insights regarding mechanisms linking modifiable environments to biological processes and long-term health outcomes already is coming into view.

Generalized Hierarchical Sparse Model for Arbitrary-Order Interactive Antigenic Sites Identification in Flu Virus Data

Recent statistical evidence has shown that a regression model by incorporating the interactions among the original covariates/features can significantly improve the interpretability for biological data. One major challenge is the exponentially expanded feature space when adding high-order feature interactions to the model. To tackle the huge dimensionality, hierarchical sparse models (HSM) are developed by enforcing sparsity under heredity structures in the interactions among the covariates. However, existing methods only consider pairwise interactions, making the discovery of important high-order interactions a non-trivial open problem. In this paper, we propose a generalized hierarchical sparse model (GHSM) as a generalization of the HSM models to tackle arbitrary-order interactions. The GHSM applies the ℓ₁ penalty to all the model coefficients under a constraint that given any covariate, if none of its associated kth-order interactions contribute to the regression model, then neither do its associated higher-order interactions. The resulting objective function is non-convex with a challenge lying in the coupled variables appearing in the arbitrary-order hierarchical constraints and we devise an efficient optimization algorithm to directly solve it. Specifically, we decouple the variables in the constraints via both the general iterative shrinkage and thresholding (GIST) and the alternating direction method of multipliers (ADMM) methods into three subproblems, each of which is proved to admit an efficiently analytical solution. We evaluate the GHSM method in both synthetic problem and the antigenic sites identification problem for the influenza virus data, where we expand the feature space up to the 5th-order interactions. Empirical results demonstrate the effectiveness and efficiency of the proposed methods and the learned high-order interactions have meaningful synergistic covariate patterns in the influenza virus antigenicity.

Longitudinal heritability of childhood aggression

The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression from the Child Behavior Checklist (CBCL) were available for 10,765 twin pairs at age 7, for 8,557 twin pairs at age 9/10, and for 7,176 twin pairs at age 12. In TEDS, parental ratings of conduct disorder from the Strength and Difficulty Questionnaire (SDQ) were available for 6,897 twin pairs at age 7, for 3,028 twin pairs at age 9 and for 5,716 twin pairs at age 12. In both studies, stability and heritability of aggressive behavioral problems was high. Heritability was on average somewhat, but significantly, lower in TEDS (around 60%) than in NTR (between 50% and 80%) and sex differences were slightly larger in the NTR sample. In both studies, the influence of shared environment was similar: in boys shared environment explained around 20% of the variation in aggression across all ages while in girls its influence was absent around age 7 and only came into play at later ages. Longitudinal genetic correlations were the main reason for stability of aggressive behavior. Individual differences in CBCL-Aggressive Behavior and SDQ-Conduct disorder throughout childhood are driven by a comparable but significantly different genetic architecture. © 2016 Wiley Periodicals, Inc.

Effects of paternal and peripubertal stress on aggression, anxiety, and metabolic alterations in the lateral septum

Early-life stress and biological predispositions are linked to mood and personality disorders related to aggressive behavior. We previously showed that exposure to peripubertal stress leads to increased anxiety-like behaviors and aggression against males and females, as well as increased aggression against females in their male offspring. Here, we investigated whether paternal (pS) and individual (iS) exposure to peripubertal stress may exert additive effects on the long-term programming of anxiety-like and aggressive behaviors in rats. Given the key role of the lateral septum (LS) in the regulation of anxiety and aggressive behaviors and the hypothesized alterations in balance between neural excitation and inhibition in aggression-related disorders, markers for these processes were examined in the LS. Peripubertal stress was applied both in naïve male rats and in the offspring of peripubertally stressed males, and anxiety-like and aggressive behaviors were assessed at adulthood. Proton magnetic resonance spectroscopy at 6-months, and post-mortem analysis of glutamic acid decarboxylase 67 (GAD67) at 12-months were conducted in LS. We confirmed that aggressive behavior was increased by pS and iS, while only iS increased anxiety-like behavior. Individual stress led to reduced GABA, confirmed by reduced GAD67 immunolabelling, and increased glutamate, N-acetyl-aspartate, phosphocholine and creatine; while pS specifically led to reduced phosphocreatine. pS and iS do not interact and exert a differential impact on the analyzed aspects of brain function and anxiety-like behaviors. These data support the view that early-life stress can affect the behavioral and neurodevelopmental trajectories of individuals and their offspring, which may involve different neurobiological mechanisms.

Modeling Impulsivity in Forensic Patients: A Three-Dimensional Model of Impulsivity

The current study investigated whether a multidimensional model could underlie impulsivity and its associations with various disorders in a forensic sample. Data were available from self-report and behavioral impulsivity instruments of 87 forensic patients. Principal component analysis (PCA) was used to derive a dimensional impulsivity model, and the relationship between and possible predictive validity of impulsivity dimensions for psychopathology was investigated using product moment correlations and regression analysis. A 3-dimensional model of impulsivity was derived, with factors labeled impulsive decision making, sensation seeking, and response inhibition. Impulsive decision making was a predictor for a history of drug dependence, the impulsive lifestyle facet of psychopathy, and antisocial personality disorder. Sensation seeking was not related to any psychopathology. Inadequate response inhibition was a predictor for drug dependence, psychopathy, and antisocial personality disorder. Given the importance of the concept of impulsivity with regard to forensic risk assessment, the current results replicated earlier impulsivity models and imply that impulsivity is a crucial target for diagnosis and interventions and underlines the importance to consider impulsivity as a multidimensional construct.

Personality disorders in adopted versus non-adopted adults

The goal of this epidemiological study was to investigate lifetime history and odds ratios of personality disorders in adopted and non-adopted adults using a nationally representative sample. Data, drawn from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), were compared in adopted (n=378) versus non-adopted (n=42,503) adults to estimate the odds of seven personality disorders using logistic regression analyses. The seven personality disorders were histrionic, antisocial, avoidant, paranoid, schizoid, obsessive-compulsive, and dependent personality disorder. Adoptees had a 1.81-fold increase in the odds of any personality disorder compared with non-adoptees. Adoptees had increased odds of histrionic, antisocial, avoidant, paranoid, schizoid, and obsessive-compulsive personality disorder compared with non-adoptees. Two risk factors associated with lifetime history of a personality disorder in adoptees compared to non-adoptees were (1) being in the age cohort 18-29 years (but no difference in the age 30-44 cohort), using the age 45 or older cohort as the reference and (2) having 12 years of education (but no difference in higher education groups), using the 0-11 years of education as the reference. These findings support the higher rates of personality disorders among adoptees compared to non-adoptees.

Genetic and Environmental Influences on Adult Mental Health: Evidence for Gene-Environment Interplay as a Function of Maternal and Paternal Discipline and Affection

Researchers have long theorized that genetic influence on mental health may differ as a function of environmental risk factors. One likely moderator of genetic and environmental influences on psychopathological symptoms is parenting behavior, as phenotypic research shows that negative aspects of parent-child relationships are associated with greater likelihood of mental illness in adulthood. The current study examined whether levels of reported parental discipline and affection experienced in childhood act as a trigger, or buffer, for adult mental health problems. Results from a nationwide twin sample suggest level of father's discipline and affection, as reported by now-adult twins, moderated genetic and environmental influences on internalizing symptoms in adulthood, such that heritability was greatest at the highest levels of discipline and affection. Father's affection also moderated the etiological influences on alcohol use problems, with greater heritability at the lowest levels of affection. No moderating effect was found for mothers. Findings suggest relationships with fathers in childhood can have long-lasting effects on the etiological influences on adult mental health outcomes.

Family history density predicts long term substance use outcomes in an adolescent treatment sample

AIMS

This study explored whether the density of family history (FH) of substance use disorders relates to post-treatment substance use outcomes in adolescents, with the primary aim of determining whether FH exerts a relatively stronger influence on longer-term outcomes.

METHOD

The present investigation examined adolescents (ages 12-18, n=366) from two independent samples who were treated for alcohol/substance use disorder (ASUD) and re-assessed during the eight years following treatment with identical methodology. Primary substance use outcomes were assessed at 1, 2, 4, 6, and 8 years post-treatment and included total drinks, days using marijuana, and days using other drugs.

RESULTS

In hierarchical linear models there were significant FH density×linear time interactions for total drinks (z=12.75, p<0.001) and marijuana use days (z=4.39, p<0.001); greater FH density predicted more total drinks and more marijuana use days, with both associations becoming stronger over time. The increasing linkage between FH and other drug use was not significant over time.

CONCLUSIONS

Findings are consistent with previous research indicating that the risk associated with FH increases over time, especially in relation to quantity/frequency measures of alcohol and marijuana use. By extending these findings to an adolescent clinical sample, the current study highlights that FH density of alcohol and drug dependence is a risk factor for poorer long-term outcomes for adolescent-onset ASUD youth as they transition into adulthood. Future work should explore the mechanisms underlying greater post-treatment substance use for adolescents/young adults with greater FH density.

Val158Met COMT polymorphism and risk of aggression in alcohol dependence

Aggression, violence and antisocial behavior are common in alcoholism, but their biological basis is poorly understood. Several studies and recent meta-analyses indicate that in schizophrenia the catecholamine-O-methyltransferase (COMT) Val158Met genotype may be associated with aggression, most often in methionine allele carriers. We tested this hypothesis in a sample of treatment-seeking alcohol-dependent in-patients (293 German patients and 499 controls, and additional 190 Polish patients as replication sample). As expected, patients with a history of violent or non-violent crime were more often male, had an earlier onset of alcoholism and more withdrawal seizures and delirium tremens, and were more likely to have a history of suicide attempts. COMT genotype was not associated with a history of violent or non-violent crime. More studies are needed on the neurobiological basis of aggression and violence in alcoholism.

Gene-environment interplay between parent-child relationship problems and externalizing disorders in adolescence and young adulthood

BACKGROUND

Previous studies have shown that genetic risk for externalizing (EXT) disorders is greater in the context of adverse family environments during adolescence, but it is unclear whether these effects are long lasting. The current study evaluated developmental changes in gene-environment interplay in the concurrent and prospective associations between parent-child relationship problems and EXT at ages 18 and 25 years.

METHOD

The sample included 1382 twin pairs (48% male) from the Minnesota Twin Family Study, participating in assessments at ages 18 years (mean = 17.8, s.d. = 0.69 years) and 25 years (mean = 25.0, s.d. = 0.90 years). Perceptions of parent-child relationship problems were assessed using questionnaires. Structured interviews were used to assess symptoms of adult antisocial behavior and nicotine, alcohol and illicit drug dependence.

RESULTS

We detected a gene-environment interaction at age 18 years, such that the genetic influence on EXT was greater in the context of more parent-child relationship problems. This moderation effect was not present at age 25 years, nor did parent-relationship problems at age 18 years moderate genetic influence on EXT at age 25 years. Rather, common genetic influences accounted for this longitudinal association.

CONCLUSIONS

Gene-environment interaction evident in the relationship between adolescent parent-child relationship problems and EXT is both proximal and developmentally limited. Common genetic influence, rather than a gene-environment interaction, accounts for the long-term association between parent-child relationship problems at age 18 years and EXT at age 25 years. These results are consistent with a relatively pervasive importance of gene-environmental correlation in the transition from late adolescence to young adulthood.

Early detection of criminality concerns and the social link

In modern societies, rhetoric focused on body and health is common as biomedical sciences have taken a big place in people’s lives. They must enhance the society, health and living conditions of citizens. Solving criminality problems remains a major challenge and the early detection of antisocial children - future offenders - promises to offer a solution to criminality thanks to science and medical advances. But in a democratic society that values ​​solidarism and pluralism and tends to preserve the social link, it is necessary to question the ethical relevance of this method of managing criminality. This paper proposes to analyze these questions in the light of debates that have troubled France for a number of years.

Family environment and attention-deficit/hyperactivity disorder in adopted children: associations with family cohesion and adaptability

BACKGROUND

Positive family environments are crucial in promoting children's emotional and behavioural well-being, and may also buffer development of attention-deficit/hyperactivity disorder (ADHD). ADHD is highly heritable, but psychosocial factors in the family environment, particularly family cohesion and communication, may mediate genetic predispositions. The purpose of the current study is to examine the mediating influence of the adoptive family environment between pre-adoptive risk factors and youths' ADHD symptomatology at 14 years post adoption.

METHODS

The data used in this study were obtained from the fourth wave of the California Long-Range Adoption Study (CLAS) (n = 449). Using structural equation modelling (SEM), family sense of coherence and family adaptability were tested as possible mediators between environmental and biological predictors and ADHD symptomatology. Predictors included birthweight, gender, age at adoption, adoption from foster care, transracial adoption status, ethnicity and having a previous diagnosis of ADHD.

RESULTS

Results show that, while adoption from foster care is negatively associated with family functioning, higher family cohesion and adaptability mediate this influence on children's ADHD symptomatology. Older age of adoption directly predicts greater ADHD symptoms with no mediating influence of the family environment.

CONCLUSIONS

The mediating influence of the family environment between children's risk factors and ADHD symptoms suggests that family intervention strategies may be helpful in improving adopted children's outcomes. Once children are adopted, targeting family communication patterns and dynamics may be an additional part of developing an evidence-based, post-adoption services toolkit.

Interaction among childhood trauma and functional polymorphisms in the serotonin pathway moderate the risk of depressive disorders

Depressive disorders are influenced by a complex interplay between genetic and environmental factors. Multiple studies support a role of serotonergic pathways in the pathophysiology of depressive disorders. As a rate-limiting enzyme of serotonin synthesis in the brain, tryptophan hydroxylase 2 (TPH2) represents a plausible candidate gene. This also applies to the serotonin reuptake transporter (5-HTTLPR) regulating the availability of serotonin in the synaptic gap. We hypothesize that functional polymorphisms (TPH2: rs7305115, 5-HTTLPR and rs25531) within both genes contribute to the risk of depressive disorders after childhood abuse in adult life. To confirm our results, we investigated two independent samples of Caucasian subjects from the study of health in Pomerania (SHIP-LEGEND: n = 2,029 and SHIP-TREND-0: n = 2,475). Depression severity was assessed by the Beck depression inventory (BDI-II) for LEGEND and the patient health questionnaire (PHQ-9) for TREND-0. Childhood abuse was assessed by the childhood trauma questionnaire. Rs7305115 (TPH2) revealed significant effects in SNP × abuse and SNP × SNP as well as in the three-way interaction. This three-way interaction among abuse, TPH2 and 5-HTTLPR showed a significant effect on depression score (p = 0.023). The SS genotype of 5-HTTLPR was associated with increased depression scores after childhood abuse only in carriers of the low-expression TPH2 GG genotype, whereas the TPH2 AA genotype reversed this effect. Our results support the role of interaction effects of genetic variants within serotonergic pathways. Genetic variants that may decrease the presynaptic serotonin concentration were associated with increased adult depressive symptoms in subjects with childhood abuse.

Child-evoked maternal negativity from 9 to 27 months: Evidence of gene-environment correlation and its moderation by marital distress

Past research has documented pervasive genetic influences on emotional and behavioral disturbance across the life span and on liability to adult psychiatric disorder. Increasingly, interest is turning to mechanisms of gene-environment interplay in attempting to understand the earliest manifestations of genetic risk. We report findings from a prospective adoption study, which aimed to test the role of evocative gene-environment correlation in early development. Included in the study were 561 infants adopted at birth and studied between 9 and 27 months, along with their adoptive parents and birth mothers. Birth mother psychiatric diagnoses and symptoms scales were used as indicators of genetic influence, and multiple self-report measures were used to index adoptive mother parental negativity. We hypothesized that birth mother psychopathology would be associated with greater adoptive parent negativity and that such evocative effects would be amplified under conditions of high adoptive family adversity. The findings suggested that genetic factors associated with birth mother externalizing psychopathology may evoke negative reactions in adoptive mothers in the first year of life, but only when the adoptive family environment is characterized by marital problems. Maternal negativity mediated the effects of genetic risk on child adjustment at 27 months. The results underscore the importance of genetically influenced evocative processes in early development.

The association between adult mortality risk and family history of longevity: the moderating effects of socioeconomic status

Studies consistently show that increasing levels of socioeconomic status (SES) and having a familial history of longevity reduce the risk of mortality. But do these two variables interact, such that individuals with lower levels of SES, for example, may experience an attenuated longevity penalty by virtue of having long-lived relatives? This article examines this interaction by analysing survival past age 40 based on data from the Utah Population Database on an extinct cohort of men born from the years 1840 to 1909. Cox proportional hazards regression and logistic regression are used to test for the main and interaction mortality effects of SES and familial excess longevity (FEL), a summary measure of an individual's history of longevity among his or her relatives. This research finds that the mortality hazard rate for men in the top 15th percentile of occupational status decreases more as FEL increases than it does among men in the bottom 15th percentile. In addition, the mortality hazard rate among farmers decreases more as FEL increases than it does for non-farmers. With a strong family history of longevity as a proxy for a genetic predisposition, this research suggests that a gene-environment interaction occurs whereby the benefits of familial excess longevity are more available to those who have occupations with more autonomy and greater economic resources and/or opportunities for physical activity.

How genes and the social environment moderate each other

Recent research has suggested that the social environment can moderate the expression of genetic influences on health and that genetic influences can shape an individual's sensitivity to the social environment. Evidence supports 4 major mechanisms: genes can influence an individual's response to environmental stress, genes may enhance an individual's sensitivity to both favorable and adverse environments, inherited characteristics may better fit with some environments than with others, and inherited capabilities may only become manifest in challenging or responsive environments. Further progress depends on better recognition of patterns of gene-environment interaction, improved methods of assessing the environment and its impact on genetic mechanisms, the use of appropriately designed laboratory studies, identification of heritable differences in an individual before environmental moderation occurs, and clarification of the timing of the impact of social and genetic moderation.

Exposure to parental smoking and child growth and development: a cohort study

Background

Studies on adverse childhood health and development outcomes associated with parental smoking have shown inconsistent results. Using a cohort of Belarusian children, we examined differences in cognition, behaviors, growth, adiposity, and blood pressure at 6.5 years according to prenatal and postnatal exposure to parental smoking.

Methods

Using cluster-adjusted multivariable regression, effects of exposure to prenatal smoking were examined by comparing (1) children whose mothers smoked during pregnancy with those of mothers who smoked neither during nor after pregnancy and (2) children whose mothers smoked during and after pregnancy with those whose mothers smoked after pregnancy only; effects of postnatal smoking were examined by comparing (1) children whose mothers smoked after pregnancy only with those of mothers who smoked neither during nor after pregnancy and (2) children whose fathers smoked with those whose fathers did not smoke among children of non-smoking mothers after adjusting for a wide range of socioeconomic and family characteristics.

Results

After adjusting for confounders, children exposed vs unexposed to prenatal maternal smoking had no differences in mean IQ, teacher-rated behavioral problems, adiposity, or blood pressure. Children exposed to maternal postnatal smoking had slightly increased behavioral problems [0.9, 95% CI: 0.6, 1.2 for total difficulties], higher body mass index [0.2, 95% CI: 0.1, 0.3], greater total skinfold thickness [0.4, 95% CI: 0.04, 0.71], and higher odds of overweight or obesity [1.4, 95% CI; 1.1, 1.7]. Similar magnitudes of association were observed with postnatal paternal smoking.

Conclusions

No adverse cognitive, behavioral and developmental outcomes were associated with exposure to maternal prenatal smoking. Observed associations with postnatal smoking of both parents may reflect residual confounding by genetic and family environmental factors.

The Early Growth and Development Study: a prospective adoption study from birth through middle childhood

The Early Growth and Development Study is a prospective adoption study of birth parents, adoptive parents, and adopted children recruited in two cohorts (N = 561 triads). The primary study aims are to examine how family, peer, and contextual processes affect children's adjustment, and to examine their interplay (mediation, moderation) with genetic influences. Participants were recruited through adoption agencies located throughout the United States following the birth of a child. Assessments are ongoing, in 9-month intervals until the child reaches 3 years of age and in 1-year intervals thereafter through age 9. Data collection includes the following primary constructs: child temperament, social behavior, school performance, mental health, and health; birth and adoptive parent personality characteristics, mental health, competence, stress, health, context, substance use, parenting, and marital relations; and pregnancy use of drugs and maternal stress during pregnancy. DNA and salivary cortisol samples have also been collected. Analyses have indicated evidence for genotype-environment interactions during early childhood. Study procedures, sample representativeness (including tests of potential confounds in the adoption design), and an overview of findings to date are summarized, and future plans are described.

Genetic risk for violent behavior and environmental exposure to disadvantage and violent crime: the case for gene-environment interaction

Despite mounds of evidence to suggest that neighborhood structural factors predict violent behavior, almost no attention has been given to how these influences work synergistically (i.e., interact) with an individual's genetic propensity toward violent behavior. Indeed, two streams of research have, heretofore, flowed independently of one another. On one hand, criminologists have underscored the importance of neighborhood context in the etiology of violence. On the other hand, behavioral geneticists have argued that individual-level genetic propensities are important for understanding violence. The current study seeks to integrate these two compatible frameworks by exploring gene-environment interactions (GxE). Two GxEs were examined and supported by the data (i.e., the National Longitudinal Study of Adolescent Health). Using a scale of genetic risk based on three dopamine genes, the analysis revealed that genetic risk had a greater influence on violent behavior when the individual was also exposed to neighborhood disadvantage or when the individual was exposed to higher violent crime rates. The relevance of these findings for criminological theorizing was considered.

Common genetic and nonshared environmental factors contribute to the association between socioemotional dispositions and the externalizing factor in children

BACKGROUND

Childhood behavioral disorders including conduct disorder (CD), oppositional defiant disorder (ODD), and attention-deficit/hyperactivity disorder (ADHD) often co-occur. Prior twin research shows that common sets of genetic and environmental factors are associated with these various disorders and they form a latent factor called Externalizing. The developmental propensity model posits that CD develops in part from socioemotional dispositions of prosociality, negative emotionality, and daring; and recent research has supported the expected genetic and environmental associations between these dispositions and CD. This study examined the developmental propensity model in relation to the broader Externalizing factor that represents the covariance among behavior disorders in children.

METHODS

Parents of 686 six- to twelve-year-old twin pairs rated them on symptoms of CD, ADHD, and ODD using the disruptive behavior disorder scale and on prosociality, negative emotionality, and daring using the child and adolescent dispositions scale. A latent factor multivariate Cholesky model was used with each disposition latent factor comprised of respective questionnaire items and the Externalizing factor comprised of symptom dimensions of CD, ADHD inattention, ADHD hyperactivity/impulsivity, and ODD.

RESULTS

Results supported the hypothesis that the socioemotional dispositions and the Externalizing factor have genetic factors in common, but there was not a single genetic factor associated with all of the constructs. As expected, nonshared environment factors were shared by the dispositions and externalizing factor but, again, no single nonshared environmental factor was common to all constructs. A shared environmental factor was associated with both negative emotionality and externalizing.

CONCLUSIONS

The developmental propensity model was supported and appears to extend to the broader externalizing spectrum of childhood disorders. Socioemotional dispositions of prosociality, negative emotionality, and (to a lesser extent) daring may contribute to the covariation among behavioral disorders and perhaps to their comorbid expression through common sets of primarily genetic but also environmental factors.

Gene-environment interactions in the etiology of human violence

This chapter reviews the current research on gene-environment interactions (G × E) with regard to human violence. Findings are summarized from both behavioral and molecular genetic studies that have investigated the interplay of genetic and environmental factors in terms of influencing violence-related behavior. Together, these studies reveal promising evidence that genetic factors combine with environmental influences to impact on the development of violent behavior and related phenotypes. G × E have been identified for a number of candidate genes implicated in violence. Moreover, the reviewed G × E were found to extend to a broad range of environmental characteristics, including both adverse and favorable conditions. As has been the case with other G × E research, findings have been mixed, with considerable heterogeneity between studies. Lack of replication together with serious methodological limitations remains a major challenge for drawing definitive conclusions about the nature of violence-related G × E. In order to fulfill its potential, it is recommended that future G × E research needs to shift its focus to dissecting the neural mechanisms and the underlying pathophysiological pathways by which genetic variation may influence differential susceptibility to environmental exposures.

Design, Utility, and History of the Colorado Adoption Project: Examples Involving Adjustment Interactions

This paper describes the Colorado Adoption Project (CAP), a longitudinal study in behavioral development, and discusses how adoption studies may be used to assess genetic and environmental etiologies of individual differences for important developmental outcomes. Previous CAP research on adjustment outcomes in childhood and adolescence which found significant interactions, including gene-environment interactions, is reviewed. New research suggests mediating effects of menarche and religiosity on age at first sex in this predominantly middle-class, Caucasian sample.

The COMT Met158 allele and violence in schizophrenia: a meta-analysis

BACKGROUND

The Met158 allele of catechol-O-methyl transferase (COMT) gene is associated with increased levels of catecholamines in the prefrontal cortex and may increase the likelihood of aggressiveness. We conducted a meta-analysis to test the hypothesis that the Met158 allele of the COMT gene is associated with aggressive and violent behavior in schizophrenia.

METHODS

MEDLINE search (12/31/11) yielded 14 studies examining the association of the COMT gene polymorphism (rs4680) and aggression in schizophrenia (total n=2219). Three separate analyses were conducted using a random effects model for Met allele carriers vs. Val/Val homozygotes, Met/Met homozygotes vs. Val allele carriers, and Met allele vs. Val allele, respectively. Primary outcome was frequency of patients with aggressive behavior and odds ratio (OR) was the effect size measure.

RESULTS

The frequency of violent patients in the sample ranged from 20% to 75%. The pooled effect sizes for the Met homozygotes vs. Val allele carriers, Met allele carriers vs. Val homozygotes and the Met allele vs. Val allele comparisons were 1.74, 1.65 and 1.35, ps<.05, respectively, suggesting that the Met 158 allele of the COMT gene is associated with higher risk for violence in schizophrenia. Results remained significant after examining heterogeneity among samples and potential publication biases.

CONCLUSIONS

The Met158 allele of the COMT gene confers a significantly increased risk for aggressive and violent behavior in schizophrenia. These data may provide basis for developing informative strategies for reducing violence in patients with schizophrenia.

Early predictors of boys' antisocial trajectories

Despite the large number of studies tracing patterns of youth antisocial behavior (AB) during adolescence, few have prospective data on the developmental precursors of AB beginning during infancy. Using a cohort of 268 low-income boys first assessed at 18 months, the current study examined predictors of early- and late-starting trajectories of AB assessed during early childhood and early adolescence. Four trajectory groups were identified, including early- and late-starting groups, a low stable group, and a high decreasing group, characterized by multiple risk factors during early childhood and early adolescence. During early childhood, parenting and maternal depression discriminated two AB trajectory groups, an early-starting and a high decreasing group, who would go on to demonstrate a high preponderance of juvenile court involvement (60% to 79%) and elevated rates of clinical depression 13 to 15 years later. The results were discussed in reference to targeting malleable family risk factors during early childhood associated with patterns of AB and mental health disorders during adolescence.

White matter abnormalities associated with disruptive behavior disorder in adolescents with and without attention-deficit/hyperactivity disorder

Disruptive behavior disorders (DBD) are among the most commonly diagnosed mental disorders in children and adolescents. Some important characteristics of DBD vary based on the presence or absence of comorbid attention-deficit/hyperactivity disorder (ADHD), which may affect the understanding of and treatment decision-making related to the disorders. Thus, identifying neurobiological characteristics of DBD with comorbid ADHD (DBD+ADHD) can provide a basis to establish a better understanding of the condition. This study aimed to assess abnormal white matter microstructural alterations in DBD+ADHD as compared to DBD alone and healthy controls using diffusion tensor imaging (DTI). Thirty-three DBD (19 with comorbid ADHD) and 46 age-matched healthy adolescents were studied using DTI. Fractional anisotropy (FA), and mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were analyzed using tract-based spatial statistics (TBSS). Significantly lower FA and higher MD, RD and AD in many white matter fibers were found in adolescents with DBD+ADHD compared to controls. Moreover, lower FA and higher RD were also found in the DBD+ADHD versus the DBD alone group. Alterations of white matter integrity found in DBD patients were primarily associated with ADHD, suggesting that ADHD comorbidity in DBD is reflected in greater abnormality of microstructural connections.

Fathering and mothering in the family system: linking marital hostility and aggression in adopted toddlers

BACKGROUND

  Previous studies have linked marital conflict, parenting, and externalizing problems in early childhood. However, these studies have not examined whether genes account for these links nor have they examined whether contextual factors such as parental personality or financial distress might account for links between marital conflict and parenting. We used an adoption design to allow for a clear examination of environmental impact rather than shared genes of parents and children, and assessments of parental personality and financial strain to assess the effects of context on relationships between marriage and parenting of both mothers and fathers.

METHOD

  Participants were 308 adoption-linked families comprised of an adopted child, her/his biological mother (BM), adoptive mother (AM) and adoptive father (AF). BMs were assessed 3-6 and 18 months postpartum and adoptive families were assessed when the child was 18 and 27 months old. Structural equations models were used to examine associations between marital hostility, fathers' and mothers' parenting hostility, and child aggressive behavior at 27 months of age. In addition, the contribution of financial strain and adoptive parent personality traits was examined to determine the associations with the spillover of marital hostility to hostile parenting.

RESULTS

  A hostile marital relationship was significantly associated with hostile parenting in fathers and mothers, which were associated with aggressive behavior in toddlers. Subjective financial strain was uniquely associated with marital hostility and child aggression. Antisocial personality traits were related to a more hostile/conflicted marital relationship and to hostile parenting.

CONCLUSIONS

  Results clarify mechanisms that may account for the success of early parent-child prevention programs that include a focus on parental economic strain and personality in addition to parent training.

Conduct disorder and adult psychiatric diagnoses: associations and gender differences in the U.S. adult population

The authors' objective was to examine the presence of Axis I and II psychiatric disorders among adult males and females with a history in childhood and/or adolescence of conduct disorder (CD). Data were derived from a large national sample of the U.S. population. Face-to-face interviews of more than 34,000 adults ages 18 years and older were conducted during 2004-2005 using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV Version. After adjusting for sociodemographic characteristics and psychiatric comorbidity, CD was associated with all Axis I and II disorders, particularly substance use disorders (SUD), bipolar disorder, and histrionic personality disorders. After adjusting for gender differences in the general population, men had significantly greater odds of social anxiety disorder and paranoid personality disorder, whereas women were more likely to have SUD. Furthermore, there was dose-response relationship between number of CD symptoms and risk for most psychiatric disorders. From a clinical standpoint, knowledge of the gender differences in associations of CD with other psychiatric disorders in adulthood may be informative of developmental pathways of the disorder, and of possible gender-specific risk factors. Early recognition and treatment of CD may help prevent the development of adult-onset disorders.

Individual differences in multiple dimensions of aggression: a univariate and multivariate genetic analysis

Previous behaviour genetic studies of aggression have yielded inconsistent results: reported heritabilities for different types of aggressive behaviour ranging from 0 to 0.98. In the present study, 247 adult twin pairs (183 MZ pairs; 64 same-sex DZ pairs) were administered seven self-report questionnaires which yielded 18 measures of aggression. Univariate genetic analyses showed moderate to high heritabilities for 14 of these 18 measures and for a general aggression factor and three correlated aggression factors extracted from the measures. Multivariate genetic analyses showed sizeable genetic correlations between the different dimensions of aggression. Thus, individual differences in many types of aggressive behaviour are attributable to some extent to genetic factors and there is considerable overlap between the genes that operate on different types of aggressive behaviour.

The Early Growth and Development Study: A Prospective Adoption Design

The Early Growth and Development Study is a prospective adoption study of birth parents, adoptive parents, and adopted children (N = 359 triads) that was initiated in 2003. The primary study aims are to examine how family processes mediate or moderate the expression of genetic influences in order to aid in the identification of specific family processes that could serve as malleable targets for intervention. Participants in the study are recruited through adoption agencies located throughout the United States, following the birth of a child. Assessments occur at 6-month intervals until the child reaches 3 years of age. Data collection includes the following primary constructs: infant and toddler temperament, social behavior, and health; birth and adoptive parent personality characteristics, psychopathology, competence, stress, and substance use; adoptive parenting and marital relations; and prenatal exposure to drugs and maternal stress. Preliminary analyses suggest the representativeness of the sample and minimal confounding effects of current trends in adoption practices, including openness and selective placement. Future plans are described.

Implications of antisocial parents

Antisocial behavior is a socially maladaptive and harmful trait to possess. This can be especially injurious for a child who is raised by a parent with this personality structure. The pathology of antisocial behavior implies traits such as deceitfulness, irresponsibility, unreliability, and an incapability to feel guilt, remorse, or even love. This is damaging to a child's emotional, cognitive, and social development. Parents with this personality makeup can leave a child traumatized, empty, and incapable of forming meaningful personal relationships. Both genetic and environmental factors influence the development of antisocial behavior. Moreover, the child with a genetic predisposition to antisocial behavior who is raised with a parental style that triggers the genetic liability is at high risk for developing the same personality structure. Antisocial individuals are impulsive, irritable, and often have no concerns over their purported responsibilities. As a parent, this can lead to erratic discipline, neglectful parenting, and can undermine effective care giving. This paper will focus on the implications of parents with antisocial behavior and the impact that this behavior has on attachment as well as on the development of antisocial traits in children.

Current research trends in early life stress and depression: review of human studies on sensitive periods, gene-environment interactions, and epigenetics

Early life stress, such as childhood abuse, neglect and loss, is a well established major risk factor for developing depressive disorders later in life. We here summarize and discuss current developments in human research regarding the link between early life stress and depression. Specifically, we review the evidence for the existence of sensitive periods for the adverse effects of early life stress in humans. We further review the current state of knowledge regarding gene×environment (G×E) interactions in the effects of early life stress. While multiple genes operate in multiple environments to induce risk for depression after early life stress, these same genes also seem to enhance the beneficial effects of a positive early environment. Also, we discuss the epigenetic mechanisms that might underlie these G×E interactions. Finally, we discuss the potential importance of identifying sensitive time periods of opportunity, as well as G×E interactions and epigenetic mechanisms, for early interventions that might prevent or reverse the detrimental outcomes of early life stress and its transmission across generations.

Social economic inequalities and mental health. I. Concepts, theories and interpretations

Summary

Aims – Reconstructing the models used for approaching the inequalities issues in health, idenfiying the most relevant theoretical and conceptual contributions. Method – Literature electronic-search on Medline, Psyclit, Econlit, Social Science Index and SocioSearch using the key-words inequalities, deprivation, poverty, socio-economic status, social class, occupational class, mental health for the period 1965-2002; integrated with manual search. The material was classified according to the conceptual and theoretical interpretative models or to the analyses of the association 'inequalities-health' where health was expressed as mortality, morbidity or services utilisation. Results – Four different interpretative models about the genesis of inequalities were identified. Further theoretical developments overcome the distinction among conceptuals contrapositions selection versus causation, statistic artefactual versus real differences, individual behaviours versus material context. Since the 80's the concept of material deprivation has been enlarged to include social deprivation to explain health inequalities. The social exclusion is related to material deprivation and to social fragility enlarging the traditional aspects of poverty. The theories that better adapt to the psychiatric field are the social selection and social causation. Conclusions – The social exclusion and the new methodologies for measuring the inequalities seems to be an effective way for understanding of the inexplored aspects of the mental health inequalities.

Declaration of Interest: This work was partly funded by the Department of the Public Health Sciences “G. Sanarelli” of the University of Rome “La Sapienza” and the Department of Medicine and Public Health of the University of Verona.

5-HTTLPR as a potential moderator of the effects of adverse childhood experiences on risk of antisocial personality disorder

INTRODUCTION

Antisocial personality disorder (ASPD) frequently co-occurs with substance dependence (SD). A functional polymorphism (5-HTTLPR) in the serotonin transporter gene has been widely studied as a risk factor for a variety of psychopathologic conditions including aggressive/violent behavior. Childhood abuse is an important predictor of ASPD. We examined 5-HTTLPR genotype and adverse childhood events (ACEs) as risk factors for ASPD in a SD sample.

MATERIALS AND METHODS

Study participants [602 European-Americans (EAs) and 779 African-Americans (AAs)] were interviewed to obtain lifetime diagnoses of ASPD and SD and information on ACEs. Triallelic genotypes for 5-HTTLPR were obtained using standard methods. We used logistic generalized estimating equations regression to examine ACEs and 5-HTTLPR genotype and their interaction as predictors of ASPD, separately by population group.

RESULTS

There were 203 (14.7%) participants diagnosed with ASPD. The frequency of the low-activity 5-HTTLPR S' allele did not differ by ASPD diagnosis, and there was no overall 5-HTTLPR×ACE interaction. However, among European-Americans, male sex (odds ratio=3.36; P<0.001) and ACE history (odds ratio=1.47; P=0.002) were significant predictors of ASPD. Among AAs, there was a significant interaction of sex×5-HTTLPR genotype×ACEs (χ=13.92, P<0.001). Among AA men, each additional ACE significantly increased the odds of ASPD irrespective of genotype, whereas among AA women, the effect of ACEs on ASPD was significant only among S' homozygotes. However, these results are limited by the small sample size in each subgroup, (particularly AA women with S'S' genotype; N=7) and require replication.

CONCLUSIONS

Childhood maltreatment contributes to the risk of ASPD, an effect for which there is preliminary evidence of moderation by 5-HTTLPR genotype in AA women.

Neurobiology of aggression and violence in schizophrenia

There is much evidence that schizophrenia patients have an increased risk for aggression and violent behavior, including homicide. The neurobiological basis and correlates of this risk have not been much studied. While genome-wide association studies are lacking, a number of candidate genes have been investigated. By far, the most intensively studied is the catechol-O-methyltransferase (COMT) gene on chromosome 22. COMT is involved in the metabolism of dopamine, a key neurotransmitter in schizophrenia pathophysiology. Several studies suggest that the Val158Met polymorphism of this gene affects COMT activity. Methionine (Met)/Met homozygote schizophrenia patients show 4- to 5-fold lower COMT activity than valine (Val)/Val homozygotes, and some but not all studies have found an association with aggression and violence. Recently, a new functional single-nucleotide polymorphism in the COMT gene, Ala72Ser, was found to be associated with homicidal behavior in schizophrenia, but this finding warrants further replication. Studies published so far indicate that an association with the monoamine oxidase A, B, or tryptophan hydroxylase 1 genes is unlikely. Data for the brain-derived neurotrophic factor gene are conflicting and limited. Data from the limited number of neuroimaging studies performed to date are interesting. Frontal and temporal lobe abnormalities are found consistently in aggressive schizophrenia patients. Positron emission tomography and single photon-emission computed tomography (SPECT) data indicate deficits also in the orbitofrontal and temporal cortex. Some functional magnetic resonance imaging studies found a negative association of violent behavior with frontal and right-sided inferior parietal activity. Neuroimaging studies may well help further elucidate the interrelationship between neurocognitive functioning, personality traits, and antisocial and violent behavior.

Allostatic processes in the family

The concepts of allostatic load and allostatic processes can help psychologists understand how health trajectories are influenced by stressful childhood experiences in the family. This paper describes psychological pathways and two key allostatic mediators, the hypothalamic–pituitary–adrenal axis and the immune system, through which stressful early rearing conditions may influence adult mental and physical health. The action of meshed gears is introduced as a metaphor to illustrate how responses occurring within a brief time frame, for example, immediate reactions to stressors, can influence developmental and health processes unfolding over much longer spans of time. We identify early-developing psychological and biological response patterns that could link chronic stressors in childhood to later health outcomes. Some of these “precursor outcomes” (e.g., heightened vigilance and preparedness for threats; enhanced inflammatory and humoral responses to infectious microorganisms) appear to be aimed at protection from immediate dangers; they may reflect “adaptive trade-offs” that balance short-term survival advantages under harsh rearing conditions against disadvantages manifested later in development. Our analysis also suggests mechanisms that underlie resilience in risky family environments.