Monoamine oxidase A and childhood adversity as risk factors for conduct disorder in females

BACKGROUND

Recent studies among males have reported a genotype-environment interaction (GxE) in which low-activity alleles at the monoamine oxidase A (MAOA) locus conferred greater sensitivity to the effects of childhood adversity on risk for conduct disorder (CD). So far, few studies of females have controlled for gene-environment correlation or used females heterozygous for this X-linked gene.

METHOD

Logistic regression analysis of a sample of 721 females ages 8-17 years from the longitudinal Virginia Twin Study of Adolescent Behavioral Development (VTSABD) assessed the additive effects of MAOA genotypes on risk for CD, together with the main effect of childhood adversity and parental antisocial personality disorder (ASP), as well as the interaction of MAOA with childhood adversity on risk for CD.

RESULTS

A significant main effect of genotype on risk for CD was detected, where low-activity MAOA imparted the greatest risk to CD in girls while controlling for the significant effects of maternal ASP and childhood adversity. Significant GxE with weak effect was detected when environmental exposure was untransformed, indicating a higher sensitivity to childhood adversity in the presence of the high-activity MAOA allele. The interaction was no longer statistically significant after applying a ridit transformation to reflect the sample sizes exposed at each level of childhood adversity.

CONCLUSIONS

The main effect of MAOA on risk for CD in females, its absence in males and directional difference of interaction is suggestive of genotype-sex interaction. As the effect of GxE on risk for CD was weak, its inclusion is not justified.

Gender differences in aggressiveness in children and adolescents at risk for schizophrenia

OBJECTIVE

This study aimed to investigate whether differences in aggression-related behavioral problems occur between boys and girls at high risk for schizophrenia living in the city of São Paulo, Brazil.

METHOD

Using the Child Behavior Checklist, we compared the prevalence of behavioral problems between genders for the offspring (6-18 years) of mothers with diagnosis of schizophrenia and a comparison group of children born to women with no severe mental disorders recruited at the gynecology outpatient clinic of the same hospital. The Structured Clinical Interview for DSM-IV Axis I Disorders, Patient Edition was applied for the evaluation of diagnostic status of mothers.

RESULTS

Male children of women with schizophrenia had a lower prevalence of aggressive behavior compared to females (4% vs. 36%; p = 0.005), whereas no gender differences regarding aggression were detected in the comparison group (24% vs. 32%; p = 0.53). Logistic regression analyses showed that male gender and being a child of women with schizophrenia interacted so as to favor lower prevalence of aggressive behavior (p = 0.03).

CONCLUSION

These findings reinforce the notion that behavioral gender differences related to schizophrenia are already detectable in childhood.

Are there meaningful etiological differences within antisocial behavior? Results of a meta-analysis

There is mounting evidence of etiologically driven distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) forms of antisocial behavior. To date, however, these differences remain somewhat speculative. The current meta-analysis of twin and adoption studies sought to clarify these distinctions by comparing meta-analytic estimates of genetic, shared environmental, and non-shared environmental influences across AGG and RB to more clearly ascertain whether they evidence differential patterns of genetic and environmental influence. A comprehensive literature search resulted in the collection of 103 twin and adoption studies, of which 15 RB samples and 19 AGG samples were ultimately included in the analyses. Results reveal clear evidence of etiological distinctions between AGG and RB. Namely, AGG appears to be a highly heritable condition (genetic factors account for 65% of the variance), with little role for the shared or common environment, particularly after childhood. By contrast, while genetic influences also contribute to RB (48% of the variance), there is an important role for shared environmental effects as well (18% of the variance). Such findings are indicative of meaningful etiologic distinctions between aggressive and rule-breaking forms of antisocial behavior, and underscore the advantage of differentiating between these behavioral subtypes when studying the causal processes that underlie antisocial behavior.

Gene—Environment Interplay and Delinquent Involvement

Behavioral genetic research has revealed that biogenic factors play a role in the development of antisocial behaviors. Much of this research has also explicated the way in which the environment and genes may combine to create different phenotypes. The authors draw heavily from this literature and use data from the National Longitudinal Study of Adolescent Health to examine genetic and environmental effects on adolescent delinquent involvement. The results of the multivariate models reveal that genetic factors have a direct effect on youthful misconduct. Most important, however, is that genetic factors interact with delinquent peers and with low self-control to predict variation in delinquency. Analysis of the Add Health data also provide evidence suggesting that there is a shared genetic pathway to delinquent involvement, to antisocial peer group formation, and to the development of low self-control.

Perspectives on oppositional defiant disorder, conduct disorder, and psychopathic features

This paper presents a few perspectives on oppositional defiant disorder (ODD), conduct disorder (CD), and early forms of psychopathy. The developmental changes and stability of each, and the interrelationship between the three conditions are reviewed, and correlates and predictors are highlighted. The paper also examines effective interventions for each of the three conditions and makes recommendations for future research.

Intergenerational linkages in antisocial behaviour

BACKGROUND

A life-course perspective was used to examine whether a parent's adolescent antisocial behaviour increases the chances of his or her child being involved in antisocial behaviour and, if so, the extent to which different aspects of parenting mediate this relationship.

AIM

It was hypothesised that there will be significant levels of intergenerational continuity in antisocial behaviour when parents have ongoing contact with the child, and that stress from parenting and ineffective parenting styles will mediate this relationship.

METHOD

Longitudinal data from the Rochester Intergenerational Study were used to test these issues in structural equation models for fathers and for mothers.

RESULTS

Parental antisocial behaviour is significantly related to child antisocial behaviour for mothers and for fathers who have frequent contact with the child, but not for fathers with infrequent contact. For mothers, the impact of adolescent antisocial behaviour on the child's antisocial behaviour is primarily mediated through parenting stress and effective parenting. For high-contact fathers there are multiple mediating pathways that help explain the impact of their adolescent antisocial behaviour on their child's behaviour.

CONCLUSIONS

The roots of antisocial behaviour extend back at least to the parent's adolescence, and parenting interventions need to consider these long-term processes.

A gene X environment interaction between DRD2 and religiosity in the prediction of adolescent delinquent involvement in a sample of males

Human behavioral phenotypes are the result of complex interactions between genotype and the environment. Still, much remains unknown about the gene X environmental basis to adolescent delinquent involvement. Using data from the National Longitudinal Study of Adolescent Health, we examine whether a polymorphism in the dopamine D2 receptor (DRD2) gene interacts with religiosity to predict variation in adolescent delinquent involvement. The results of the analyses revealed a gene X environment interaction between the A-1 allele of DRD2 and religiosity in the prediction of adolescent delinquency. Limitations are noted, and the implications of the findings are discussed.

The interaction between genetic risk and childhood sexual abuse in the prediction of adolescent violent behavior

A rich line of empirical research has indicated that antisocial behaviors are the result of genetic factors and environmental factors working interactively. The current study uses this knowledge base as a springboard to examine the effects of childhood sexual abuse and genetic risk in the prediction of adolescent violent delinquency. To address this issue, data from the National Longitudinal Study of Adolescent Health were analyzed. The results of the analyses reveal that childhood sexual abuse interacts with genetic risk to predict involvement in violent delinquency for males. The effects of childhood sexual abuse and genetic risk as well as the interaction between the two are unrelated to violent delinquency for females. Implications of the study are discussed.

The heritability of life events: an adolescent twin and adoption study

Although life events are often conceptualized as reflecting exogenous risk factors for psychopathology, twin studies have suggested they are heritable. We undertook a mixed twin/adoption study to further explore genetic and environmental contributions to individual differences in the experience of life events. Specifically, a sample of 618 pairs of like-sex adolescent twins, 244 pairs of like-sex adopted adolescent and young adult siblings, and 128 pairs of like-sex biological siblings completed a life events interview. Events were classified as independent (not likely to have been influenced by respondent's behavior), dependent (likely to have been influenced by respondent's behavior), or familial (experienced by a family member), and then summed to form three life event scales. Variance on the scales was assumed to be a function of four factors: additive genetic effects (a2), shared environmental effects (c2), twin-specific effects (t2), and nonshared environmental effects (e2). Data were analyzed using standard biometrical models. Shared environmental effects were found to be the largest contributor to variance in familial events (c2 = .71; 95% confidence interval of .65, .76); additive genetic effects were the largest contributor to dependent events (a2 = .45; CI = .31, .58); and nonshared environmental effects were found to be the largest contributor independent events (e2 = .57; CI = .51, .64). A significant twin-specific effect was also found for independent life events, indicating that twins are more likely to be exposed to such events than non-twin biological siblings. Findings are discussed in terms of their implication for understanding the nature of psychosocial risk.

Differential genetic and environmental influences on reactive and proactive aggression in children

While significant heritability for childhood aggression has been claimed, it is not known whether there are differential genetic and environmental contributions to proactive and reactive forms of aggression in children. This study quantifies genetic and environmental contributions to these two forms of aggression in an ethnically diverse urban sample of 9-10 year old twins (N = 1219), and compares results across different informants (child self-report, mother, and teacher ratings) using the Reactive-Proactive Aggression Questionnaire (RPQ). Confirmatory factor analysis of RPQ items indicated a significant and strong fit for a two-factor proactive-reactive model which was significantly superior to a one-factor model and which replicated across gender as well as the three informant sources. Males scored significantly higher than females on both self-report reactive and proactive aggression, findings that replicated on mother and teacher versions of the RPQ. Asian-Americans scored lower than most ethnic groups on reactive aggression yet were equivalent to Caucasians on proactive aggression. African-Americans scored higher than other ethnic groups on all measures of aggression except caregiver reports. Heritable influences were found for both forms of aggression across informants, but while boys' self-reports revealed genetic influences on proactive (50%) and reactive (38%) aggression, shared and non-shared environmental influences almost entirely accounted for girls' self-report reactive and proactive aggression. Although genetic correlations between reactive and proactive aggression were significant across informants, there was evidence that the genetic correlation was less than unity in boys self reported aggression, indicating that genetic factors differ for proactive and reactive aggression. These findings provide the first evidence for varying genetic and environmental etiologies for reactive and proactive aggression across gender, and provide additional support for distinction between these two forms of aggression.

Dimensional representations of DSM-IV cluster B personality disorders in a population-based sample of Norwegian twins: a multivariate study

BACKGROUND

The personality disorders (PDs) in the 'dramatic' cluster B [antisocial (ASPD), histrionic (HPD), narcissistic (NPD) and borderline (BPD)] demonstrate co-morbidity. However, the degree to which genetic and/or environmental factors influence their co-occurrence is not known and, with the exception of ASPD, the relative impact of genetic and environmental risk factors on liability to the cluster B PDs has not been conclusively established.

METHOD

PD traits were assessed in 1386 Norwegian twin pairs between the age of 19 and 35 years using the Structured Interview for DSM-IV Personality Disorders (SIDP-IV). Using the statistical package Mx, multivariate twin models were fitted to dimensional representations of the PDs.

RESULTS

The best-fitting model, which did not include sex or shared family environment effects, included common genetic and environmental factors influencing all four dramatic PD traits, and factors influencing only ASPD and BPD. Heritability was estimated at 38% for ASPD traits, 31% for HPD traits, 24% for NPD traits and 35% for BPD traits. BPD traits had the lowest and ASPD traits the highest disorder-specific genetic variance.

CONCLUSION

The frequently observed co-morbidity between cluster B PDs results from both common genetic and environmental influences. Etiologically, cluster B has a 'substructure' in which ASPD and BPD are more closely related to each other than to the other cluster B disorders.

Temperament and parenting during the first year of life predict future child conduct problems

Predictive associations between parenting and temperament during the first year of life and child conduct problems were assessed longitudinally in 1,863 offspring of a representative sample of women. Maternal ratings of infant fussiness, activity level, predictability, and positive affect each independently predicted maternal ratings of conduct problems during ages 4-13 years. Furthermore, a significant interaction indicated that infants who were both low in fussiness and high in predictability were at very low risk for future conduct problems. Fussiness was a stronger predictor of conduct problems in boys whereas fearfulness was a stronger predictor in girls. Conduct problems also were robustly predicted by low levels of early mother-report cognitive stimulation when infant temperament was controlled. Interviewer-rated maternal responsiveness was a robust predictor of conduct problems, but only among infants low in fearfulness. Spanking during infancy predicted slightly more severe conduct problems, but the prediction was moderated by infant fussiness and positive affect. Thus, individual differences in risk for mother-rated conduct problems across childhood are already partly evident in maternal ratings of temperament during the first year of life and are predicted by early parenting and parenting-by-temperament interactions.

Understanding development and prevention of chronic physical aggression: towards experimental epigenetic studies

The aim of this paper was to highlight how developmental psychopathology, epigenetics and prevention experiments are starting to blend together to explain the developmental causes of chronic physical aggression (CPA) and, more importantly, to help prevent CPA and its associated physical, mental and social problems. After defining the keywords (prevention, chronic and physical aggression), a selected review of published studies is used to answer the following four questions: when should we attempt to prevent onset of CPA? What are the risk factors for CPA? Have early childhood interventions been shown to prevent CPA? Can early preventive interventions benefit from epigenetic studies? The last section of this paper gives two examples of experimental prevention designs that integrate present knowledge of CPA development, risk factors, early childhood preventive interventions and epigenetic programming of brain development during pregnancy and early childhood. I conclude that randomized control trials of preventive interventions during pregnancy and early childhood with a specific focus on epigenetic effects are the research design most likely to advance our understanding of the biopsychosocial mechanisms that lead to CPA, and the only research design that can identify effective interventions for preventing the development of CPA.

How can the study of biological processes help design new interventions for children with severe antisocial behavior?

Children with severe antisocial behavior have an increased risk of showing violently aggressive and other forms of problem behavior in adolescence and adulthood. It is well established that both biological and social factors are involved in the development of antisocial behavior. The primary aim of this paper is to discuss the evidence that specific neurobiological systems are involved in the etiology of childhood-onset antisocial behavior. These factors are responsible for the severity of the behavioral problems observed in antisocial children, but they also play a role in their persistence, because they influence children's interactions with their environment. We will discuss the possible causes of disruptions in neurobiological systems in childhood antisocial behavior and point out the implications of these findings for theory and clinical practice. We will argue that familial factors (e.g., genetic influences, early childhood adversity) are linked to negative behavioral outcomes (e.g., antisocial behavior problems) through the mediating and transactional interplay with neurobiological deficits. An investigation of neurobiological functioning in antisocial children might not only indicate which children are most likely to persist in engaging in severe antisocial behavior, but also guide the development of new interventions.

The impact of parental stressors on the intergenerational transmission of antisocial behavior

We examine the extent to which parental antisocial behavior is related to child antisocial behavior and, if it is, the extent to which the effect is mediated by parental stressors and by parenting behaviors. In particular, we examine two sources of stress-depressive symptoms and exposure to negative life events. The study is based on data from the Rochester Intergenerational Study, a prospective multi-generation panel study. The parent sample is 73% male and 27% female and predominantly African American (69%); the child sample consists of each parent's oldest biological child. We find significant levels of intergenerational continuity in antisocial behavior for mothers and for fathers who live with or supervise their child, but not for fathers who have low levels of contact with their child. Results of structural equation models of mediating pathways are similar for mothers and for supervisory fathers. Of the two stressors we examine, depressive symptoms appears to be the more consistent mediator. It, both directly and indirectly via its impact on parenting behaviors, influences the child's early onset of antisocial behavior. The results imply that childhood antisocial behavior has deep roots, extending back to the parent's adolescent development.

Rural environments reduce the genetic influence on adolescent substance use and rule-breaking behavior

BACKGROUND

There is increasing evidence that certain environmental factors can modify genetic effects. This is an important area of investigation as such work will help to guide the development of new intervention programs. In this paper, we address whether rural environments moderate the genetic influence on adolescent substance use and rule-breaking behavior (i.e. externalizing psychopathology).

METHOD

Over 1200 Minnesotan 17-year-old twins were classified as either urban or rural. Externalizing behavior was operationalized as the use and abuse of alcohol and drugs along with symptoms of conduct, oppositional defiant, and antisocial personality disorders. Biometric factor modeling estimated whether the relative contribution of genetic and shared environmental factors varied from urban to rural settings.

RESULTS

Residency effects reached statistical significance in the male sample only. In urban environments, externalizing behavior was substantially influenced by genetic factors, but in rural environments, shared environmental factors became more influential. This was apparent at both the individual-variable and factor levels.

CONCLUSIONS

These findings suggest a gene-environment interaction in the development of male adolescents' problem behaviors, including substance use. The results fit within an expanding literature demonstrating both the contextual nature of the heritability statistic and how certain environments may constrain the expression of genetic tendencies.

Genetics of personality disorders

This review of the literature on genetic contributions to the etiology of personality disorders broadly follows the DSM classification, and begins by evaluating the current evidence for genetic influences on the DSM axis II disorders. One of the most exciting directions in psychiatric genetics is the rapidly developing field of molecular genetic studies aiming to identify specific genes correlated with psychiatric phenotypes. Personality disorders, like most other psychiatric diagnostic categories, are etiologically complex, which implies that they are influenced by several genes and several environmental factors. The interplay between genes and the environment is a field that is receiving increasing attention and is addressed both in relation to quantitative and molecular methods.

Gene-environment interaction between peer victimization and child aggression

Although peer victimization places children at serious risk for aggressive behavior, not all victimized children are aggressive. The diathesis-stress hypothesis of disease proposes that an environmental stressor such as peer victimization should to lead to maladjustment mostly in those individuals with preexisting genetic vulnerabilities. Accordingly, this study examined whether the link between peer victimization and child aggression is moderated by children's genetic risk for such behavior. Using a sample of 506 6-year-old twins, peer victimization was assessed through peer nominations and aggressive behavior was assessed through peer and teacher reports. Children's genetic risk for aggression was estimated as a function of their co-twin's aggression and the pair's zygosity. Genetic modeling showed that peer victimization is an environmentally driven variable that is unrelated to children's genetic disposition. Results also provided support for the notion of a gene-environment interaction between peer victimization and child's genetic risk for aggressive behavior, albeit only in girls. For boys, peer victimization was related to aggression regardless of the child's genetic risk for such behavior. Different socialization experiences in girls' compared to boys' peer groups may explain the different pattern of results for girls and boys.

Quantitative genetic studies of antisocial behaviour

This paper will broadly review the currently available twin and adoption data on antisocial behaviour (AB). It is argued that quantitative genetic research can make a significant contribution to further the understanding of how AB develops. Genetically informative study designs are particularly useful for investigating several important questions such as whether: the heritability estimates vary as a function of assessment method or gender; the relative importance of genetic and environmental influences varies for different types of AB; the environmental risk factors are truly environmental; and genetic vulnerability influences susceptibility to environmental risk. While the current data are not yet directly translatable for prevention and treatment programmes, quantitative genetic research has concrete translational potential. Quantitative genetic research can supplement neuroscience research in informing about different subtypes of AB, such as AB coupled with callous-unemotional traits. Quantitative genetic research is also important in advancing the understanding of the mechanisms by which environmental risk operates.

On the nature and nurture of antisocial behavior and violence

This article focuses on the contribution that behavioral genetic research can make to further the understanding of how antisocial and violent behavior develops. Genetically informative study designs are particularly useful for investigating etiological heterogeneity and can refine the search for developmental pathways to persistent antisocial conduct. While the current data are not yet directly translatable for prevention programs, behavioral genetic research will have far-reaching implications for prevention and treatment. As we find genes associated with risk for antisocial behavior and develop better understanding of the mechanics of the interplay between genes and the environment, we can expect to tailor prevention and treatment to serve the specific needs of etiologically distinct subgroups of children. Furthermore, researchers involved in sharpening the knowledge base have the responsibility of trying to ensure that such findings are not misused.

Externalizing disorders in the offspring from the San Diego prospective study of alcoholism

OBJECT

Conduct disorder (CD) and attention deficit hyperactivity disorder (ADHD) may be more prevalent in relatives of alcoholics and may predict alcohol and drug problems, but not all studies agree. This paper evaluates these questions in well-educated families of alcoholics and controls.

METHODS

Data from 165, 14-25-year-old offspring in the San Diego Prospective Study were used to create Group 1 (n=17) with CD or ADHD and Group 2 (n=148) with no such diagnoses. Correlations and hierarchical logistic regressions evaluated characteristics associated with these disorders, comparing the impact of CD and ADHD.

RESULTS

The rates of CD (6.1%) and of ADHD (4.8%) were not strikingly elevated, and did not relate to the family history of alcohol or drug use disorders. Group 1 offspring were more likely to have divorced parents, a relative with bipolar disorder, a higher intake of alcohol and illicit substances, and associated problems.

Preliminary evidence that specific candidate genes are associated with adolescent-onset antisocial behavior

Though initially conceptualized as resulting from peer imitation of child-onset or life-course-persistent youth [Moffitt, 1993], there is mounting evidence from twin studies that adolescent-onset or adolescent-limited antisocial behavior may also be genetically influenced. This study sought to provide preliminary molecular genetic evidence in support of these findings. We further evaluated whether genetic associations varied between behavioral subtypes of ASB (i.e., physical aggression and nonaggressive rule-breaking), given that only the latter has been found to characterize adolescent-onset ASB. The sample consisted of 211 undergraduate men of European-American ancestry. Three polymorphisms with theoretical and/or empirical ties to ASB or related traits (i.e., tryptophan hydroxylase-A218C, 5HT(2A) His452Tyr, and the DAT1 variable nucleotide tandem repeat) were genotyped. Analyses revealed that two of the three polymorphisms (i.e., His452Tyr and DAT1) were associated with adolescent ASB. Moreover, these associations appeared to be specific to the nonaggressive, rule-breaking form of ASB, and did not extend to physical aggression, further supporting ties to adolescent ASB in particular. Such results thus constructively replicate earlier findings of genetic influence on adolescent ASB. They also offer preliminary evidence that the genetic processes underlying aggressive and nonaggressive antisocial behavior may be (at least partially) distinct.

Conduct disorder among Asians and Native Hawaiian/Pacific Islanders in the USA

BACKGROUND

Conduct disorder (CD) is a relatively common disorder of childhood and adolescence in the USA with substantial associated morbidity, yet little has been published on CD among Asians and Native Hawaiian/Pacific Islanders (NH/PI) in the USA.

METHOD

We used the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) to examine the prevalence and correlates of retrospectively reported CD within Asians and NH/PI (18 years and older). We also completed logistic regressions to explore factors associated with CD within Asians (n=1093) and, separately, NH/PI (n=139) and to explain racial differences in CD prevalence.

RESULTS

Asians were about a third as likely [odds ratio (OR) 0.4, 95% confidence interval (CI) 0.22-0.58] whereas NH/PI were about two and half times more likely (OR 2.6, 95% CI 1.31-5.06) to have had CD compared with Caucasian respondents. Within Asians and NH/PI, CD was strongly associated with adult antisocial behavior, substance use and affective disorders. Demographic factors, the age that subjects came to the USA, measures of family environment and family history could not explain the observed differences in prevalence of CD for NH/PI relative to Caucasians.

CONCLUSIONS

Asian and NH/PI youth with CD represent a subgroup of Asian youth at very high risk for a number of serious psychiatric disorders. Further investigation is needed to explain the high CD prevalence among NH/PI.

A genetically informative developmental study of the relationship between conduct disorder and peer deviance in males

BACKGROUND

Conduct disorder (CD) and peer deviance (PD) both powerfully predict future externalizing behaviors. Although levels of CD and PD are strongly correlated, the causal relationship between them has remained controversial and has not been examined by a genetically informative study.

METHOD

Levels of CD and PD were assessed in 746 adult male-male twin pairs at personal interview for ages 8-11, 12-14 and 15-17 years using a life history calendar. Model fitting was performed using the Mx program.

RESULTS

The best-fit model indicated an active developmental relationship between CD and PD including forward transmission of both traits over time and strong causal relationships between CD and PD within time periods. The best-fit model indicated that the causal relationship for genetic risk factors was from CD to PD and was constant over time. For common environmental factors, the causal pathways ran from PD to CD and were stronger in earlier than later age periods.

CONCLUSION

A genetically informative model revealed causal pathways difficult to elucidate by other methods. Genes influence risk for CD, which, through social selection, impacts on the deviance of peers. Shared environment, through family and community processes, encourages or discourages adolescent deviant behavior, which, via social influence, alters risk for CD. Social influence is more important than social selection in childhood, but by late adolescence social selection becomes predominant. These findings have implications for prevention efforts for CD and associated externalizing disorders.

From conduct disorder to severe mental illness: associations with aggressive behaviour, crime and victimization

BACKGROUND

Conduct disorder (CD) prior to age 15 has been associated with an increased risk of aggressive behaviour and crime among men with schizophrenia. The present study aimed to replicate and extend this finding in a clinical sample of severely mentally ill men and women.

METHOD

We examined a cohort of in-patients with severe mental illness in one mental health trust. A total of 205 men and women participated, average age 38.5 years. CD was diagnosed using a structured diagnostic tool. Alcohol and illicit drug use, aggressive behaviour and victimization were self-reported. Information on convictions was extracted from official criminal records. Analyses controlled for age and sex.

RESULTS

CD prior to age 15 was associated with an increased risk of assault over the lifespan [odds ratio (OR) 3.98, 95% confidence interval (CI) 1.87-8.44)], aggressive behaviour in the 6 months prior to interview (OR 2.66, 95% CI 1.24-5.68), and convictions for violent crimes (OR 3.19, 95% CI 1.46-6.97) after controlling for alcohol and illicit drug use. The number of CD symptoms present prior to age 15 significantly increased the risk of serious assaults over the lifespan, aggressive behaviour in the past 6 months, and violent crime after controlling for alcohol and illicit drug use.

CONCLUSIONS

Men and women with severe mental illness who have a history of CD by mid-adolescence are at increased risk for aggressive behaviour and violent crime. These patients are easily identifiable and may benefit from learning-based treatments aimed at reducing antisocial behaviour. Longitudinal, prospective investigations are needed to understand why CD is more common among people with than without schizophrenia.

Incorporating the family as a critical context in genetic studies of children: implications for understanding pathways to risky behavior and substance use

The availability of candidate gene markers for biobehavioral traits will undoubtedly result in increasing attention to genetic influences in studies of childhood risk factors for health behaviors. However, a strict emphasis on genomics without consideration of the social contexts that give rise to risky behaviors will miss opportunities to understand more fully the powerful effect of the family on childhood development. This article discusses the rationale for using the family as a critical context for studying the translation of genetic propensity for risky behavior into developmental pathways that span childhood and adolescence. Attention is given to the importance of family environmental factors; the emerging literature on genetic influences on potential intermediate phenotypes; the need for rich and detailed characterizations of both phenotypes and environmental risk factors embedded within genomic studies of children; and implications for interventions and preventions aimed at risky behaviors. Via discussion of these issues, pragmatic considerations of how studying families as a context may facilitate the thoughtful inclusion of children into genetic paradigms are emphasized.

Depression and internally directed aggression: genetic and environmental contributions

This study uses behavior genetic (BG) methodology to investigate Freud's theory of depression as aggression directed toward the self (1930) and the extent to which genetically and environmentally influenced aggressive tendencies contribute to depressive symptoms. Data from the Twin and Offspring Study in Sweden (TOSS) is used to demonstrate how, in estimating shared and unique environmental influences, BG methods can inform psychoanalytic theory and practice, particularly because of their shared emphasis on the importance of individual experience in development. The TOSS sample consists of 909 pairs of adult twins, their partners, and one adolescent child per couple. The Center for Epidemiologic Studies Depression Scale (Radloff 1977) was used to measure depressive symptoms and the Karolinska Scales of Personality (Schalling and Edman 1993) to measure internally directed aggression. Genetic analyses indicated that for both men and women, their unique experiences as well as genetic factors contributed equally to the association between internally directed aggression and depressive symptoms. These findings support Freud's theory that constitutionally based differences in aggression, along with individual experiences, contribute to a person's depressive symptoms. Establishing that an individual's unique, not shared, experiences and perceptions contribute to depressive symptoms and internally directed aggression reinforces the use of patient-specific treatment approaches implemented in psychoanalytic psychotherapy or psychoanalysis.

The limited role of neuroimaging in determining criminal liability: an overview and case report

OBJECTIVE

Studies indicate there is a substantial biological substrate for psychopathic behavior. Neuroimaging techniques have afforded biomedical sciences a means to investigate further how aberrant brain activity or structure may be correlated with psychopathy and violence. This paper will provide an overview of the literature, and then will explore the role of structural and functional MRI brain imaging in the defense of a young adult male charged with kidnapping and rape.

METHOD

Using Pubmed and the keywords "functional neuroimaging," "structural neuroimaging," "psychopathy," "antisocial personality," "sociopathy," "aggression," "impulsivity," and "violence," the authors conduct a review of structural and functional neuroimaging studies involving aggressive, violent, psychopathic or antisocial offenders. We then provide a case report of a defendant, charged with kidnapping and rape, who was found during a forensic evaluation to have abnormal neuroimaging findings.

RESULTS

The defendant's counsel was able to present in his client's defense multiple indicators of brain dysfunction and psychiatric illness partially substantiated by brain imaging.

CONCLUSIONS

The extent to which neuroimaging findings can be used as exculpatory or mitigating evidence remains the subject of much debate. Neuroimaging is just one piece of evidence the forensic expert relies on in determining the extent of neuropathology and mental illness. As illustrated in the case report, imaging studies most often will serve a mitigating role, affording the courts an opportunity to tailor punishment, provide court-ordered treatment, and potentially decrease recidivism.

Case-control and within-family tests for an association between conduct disorder and DAT1

BACKGROUND

Conduct disorder (CD) is characterized by a persistent pattern of violating age-appropriate norms and the rights of others, and is one of the most frequently diagnosed disorders among children. CD is moderately heritable, but we know of no reliable associations with specific genes. Evidence suggests that a variable number tandem repeat polymorphism of the dopamine transporter (DAT1) gene may be associated with externalizing behavior in children.

OBJECTIVE

To test for an association between the DAT1 gene and CD.

DESIGN

Case-control analyses and a transmission disequilibrium test (TDT) were conducted.

SETTING/PARTICIPANTS

Cases were (n=210) adolescents enrolled in a Colorado treatment program for conduct and substance use problems. Controls included adolescents matched to the probands in the treatment program and their siblings (n=162). The TDT was conducted using case families in which DNA from both parents was available (95 trios).

RESULTS

The case-control analysis of the full sample did not result in a significant association [chi2 (2,372)=0.13, P=0.94]. Cases with early-onset conduct problems had slightly more 10-repeat alleles than controls, although this difference was not significant [chi2 (2,264)=2.19, P=0.33, 9/10 odds ratio (OR)=1.58, 10/10 OR=2.14]. The TDT also did not result in a significant association [chi2(1)=0.12, P=0.94].

CONCLUSION

Results did not support an association between this polymorphism of the DAT1 gene and CD in adolescents.

Heterogeneity in antisocial behaviours and comorbidity with depressed mood: a behavioural genetic approach

BACKGROUND

Antisocial behaviour is often comorbid with depressed mood but is itself a collection of heterogeneous behaviours. Using a genetically informative design, we examine heterogeneity in antisocial behaviour and overlaps between different forms of antisocial behaviour with depressed mood.

METHODS

Data were drawn from the G1219 large-scale community sample containing self-report questionnaire data from 941 twin pairs and 328 sibling-pairs aged 12-21 years.

RESULTS

Inter-correlations among oppositionality, physical aggression and delinquency, and between the antisocial subscales and depressed mood, were mediated by genetic and non-shared environmental influences. Genetic factors generally contributed more to the correlations than the non-shared environment.

CONCLUSIONS

These results indicate that many genetic and non-shared environmental influences were common to all the traits studied, but there was also evidence for trait-specific effects.

The Behavioral Genetics of Personality Disorder

Behavioral genetics research has opened a new window on understanding personality disorder. The earliest studies were focused on establishing the relative contributions of genes and the environment in these disorders. Although these studies provided solid evidence of the importance of genetic and environmental influences on personality disorder and showed that all aspects of personality disorder are subject to genetic influence, heritability studies are limited because they are not helpful in explicating causal mechanisms. More recent research has focused on the relative contributions of the covariation of personality disorder diagnoses and traits, which allows one to examine etiological relationships. These developments are leading to major changes in ideas about what constitutes the environment and nature of the interplay between genes and environment. The present review examines major themes in this growing body of research in the context of current issues in the personality disorders.

Father-child transmission of antisocial behavior: the moderating role of father's presence in the home

OBJECTIVE

To demonstrate an environmental effect of being raised by an antisocial father and to test whether the transmission of antisocial behavior from father to child is moderated by the father's presence in the home.

METHOD

A community sample of male and female 11- and 17-year-old twins and their biological parents participating in the Minnesota Twin Family Study was used. A series of hierarchical linear regression models was used to examine the relationship between father antisociality and his children's externalizing psychopathology and to determine whether the father's time spent in the home moderated this relationship. Models controlled for the child's sex.

RESULTS

A significant main effect of both father's antisociality and father's presence on the children's externalizing psychopathology was found: Children born to antisocial fathers evidenced higher rates of externalizing behavior, and children raised without their biological father in the home exhibited more externalizing behaviors. The interaction was also significant such that the association between father and child antisociality was stronger when the father was present for a longer period of the child's life. Furthermore, when fathers show high levels of antisociality, fathers' presence appears to have deleterious rather than beneficial effects on child behavior.

CONCLUSIONS

The present results suggest the transmission of antisociality from father to child is at least partially environmentally moderated.

Rethinking Timing of First Sex and Delinquency

The relation between timing of first sex and later delinquency was examined using a genetically informed sample of 534 same-sex twin pairs from the National Longitudinal Study of Adolescent Health, who were assessed at three time points over a 7-year interval. Genetic and environmental differences between families were found to account for the association between earlier age at first sex and increases in delinquency. After controlling for these genetic and environmental confounds using a quasi-experimental design, earlier age at first sex predicted lower levels of delinquency in early adulthood. The current study is contrasted with previous research with non-genetically informative samples, including Armour and Haynie. Results suggest a more nuanced perspective on the meaning and consequences of adolescent sexuality than is commonly put forth in the literature.

Common genetic and environmental influences on major depressive disorder and conduct disorder

The evidence for common genetic and environmental influences on conduct disorder (CD) and major depressive disorder (MDD) in adolescents was examined. A sample of 570 monozygotic twin pairs, 592 dizygotic twin pairs, and 426 non-twin siblings, aged 12-18 years, was recruited from the Colorado Twin Registry. For the past year data, there was a significant correlation between the genetic influences on MDD and CD and, for the lifetime data, there was a significant correlation between the genetic influences on MDD and CD, and a significant correlation between the nonshared environmental influences on MDD and CD. Our results suggest that some genetic factors will increase an individual's vulnerability to both MDD and CD in adolescence.

Genetic effects on male sexual coercion

The genetic and environmental influences on sexual coercion, and to what extent its associations with alcohol use and psychopathy depend on shared genetic and environmental effects, were explored in a Finnish population-based sample of 938 men, aged 33-43 years, using the classical twin study design. All three phenotypes were associated positively and affected by genes (sexual coercion 28%, alcohol use 60%, psychopathy 54%), with 46% of the correlation between sexual coercion and psychopathy, 89% of the correlation between alcohol use and psychopathy and 100% of the correlation between sexual coercion and alcohol use being explained by shared genetic effects. Further, the results showed that a proportion of the variance in sexual coercion was derived from a highly genetic source that was common with alcohol use and psychopathy. This latent factor was hypothesized to reflect a general tendency for antisocial behavior that is pervasive across different situations. Relevant theories on sexual coercion were discussed in light of the results.

Genetic and environmental contributions to prosocial behaviour in 2- to 9-year-old South Korean twins

Although over 50 twin and adoption studies have been performed on the genetic architecture of antisocial behaviour, far fewer studies have investigated prosocial behaviour, and none have done so on a non-western population. The present study examined mothers' ratings of prosocial behaviour in 514 pairs of 2- to 9-year-old South Korean monozygotic and dizygotic twins. Correlational analyses showed a tendency of increasing genetic effects and decreasing shared environmental effects with age although shared family environment effects and the moderating effects of age did not attain statistical significance in model-fitting analyses. The best-fitting model indicated that 55% (95% CI: 45–64%) of the variance in the 2- to 9-year-olds' prosocial behaviour was due to genetic factors and 45% (95% CI: 36–55%) was due to non-shared environmental factors. It is concluded that genetic and environmental influences on prosocial behaviour in young South Koreans are mostly similar to those in western samples.

Research review: DSM-V conduct disorder: research needs for an evidence base

This article charts a strategic research course toward an empirical foundation for the diagnosis of conduct disorder in the forthcoming DSM-V. Since the DSM-IV appeared in 1994, an impressive amount of new information about conduct disorder has emerged. As a result of this new knowledge, reasonable rationales have been put forward for adding to the conduct disorder diagnostic protocol: a childhood-limited subtype, family psychiatric history, callous-unemotional traits, female-specific criteria, preschool-specific criteria, early substance use, and biomarkers from genetics, neuroimaging, and physiology research. This article reviews the evidence for these and other potential changes to the conduct disorder diagnosis. We report that although there is a great deal of exciting research into each of the topics, very little of it provides the precise sort of evidence base required to justify any alteration to the DSM-V. We outline specific research questions and study designs needed to build the lacking evidence base for or against proposed changes to DSM-V conduct disorder.

Cognition to Genes via the Brain in the Study of Conduct Disorder

Although a single diagnostic label, conduct disorder, is currently applied to children exhibiting antisocial behaviour, multiple routes to the same behavioural phenomena exist. Morton and Frith's (1995) causal modelling has been fundamentally important in influencing models of cognitive/affective and associated neural differences between callous-unemotional (CU) and reactive/threat-based antisocial behaviour. Current behavioural genetic research is still catching up with the developmental cognitive neuroscience, and very few genetically informative studies differentiate between these two subtypes of antisocial behaviour. Our own work with preadolescent twins suggests that while the CU subtype is genetically vulnerable to antisocial behaviour, the non-CU subtype manifests a primarily environmental aetiology to their antisocial behaviour. Molecular genetic work to date has not differentiated between these two subtypes, and we highlight why it might be of interest to do so. Finally, we discuss how the novel approach of imaging genetics could be harnessed to study genes to cognition pathways for different subtypes of conduct disorder. Uta Frith's contributions to articulating research strategies for developmental disorders are important in conducting and interpreting this work.

ADHS, Antisoziale Persönlichkeitsstörung und Delinquenz 1Prof. Dr. med. Dr. jur. R. Luthe zum 75. Geburtstag gewidmet

Die Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) kann im Erwachsenenalter mit erheblichen Einschränkungen im Lebensalltag vergesellschaftet sein. In Straftäterpopulationen kommt ADHS sowohl bei Männern wie auch Frauen überdurchschnittlich häufig vor. In der Regel ist dabei ADHS mit einer Conduct Disorder (CD) assoziiert. Bei der Kombination ADHS mit CD handelt es sich um Personen, bei denen in der Kindheit und Jugend delinquente Verhaltensstile zu beobachten sind. Bei diesem Personenkreis, nicht aber bei isolierter ADHS, besteht ein hohes Risiko für die Entwicklung einer Antisozialen Persönlichkeitsstörung (ASP) oder von anhaltendem kriminellem Verhalten im Erwachsenenalter. Etwa die Hälfte aller Kinder mit ADHS entwickelt eine CD. Eine ASP tritt später in 20–25 % der Fälle ein. Auf welche Weise ADHS mit CD oder ASP pathogenetisch assoziiert ist, konnte bisher nicht eindeutig geklärt werden. Gemeinsame genetische Faktoren, Gen × Gen Interaktionen sowie Gen × Umwelt Interaktionen sind wahrscheinlich. Straftäter mit ADHS beginnen in jüngerem Alter mit delinquenten Verhaltensstilen und sind häufiger Rezidivtäter als Täter ohne ADHS. Die Prävalenz von ADHS ist nicht in allen Tätergruppen gleichmäßig erhöht. Bei Betrügern ist die ADHS Prävalenz normal. Signifikant mehr ADHS findet man bei Sexualstraftätern (ca. 30 %) und bei Personen, die reaktive Gewalttaten verübt haben. Bei proaktiver Gewalttätigkeit ist die Prävalenz für ADHS eher niedrig. Auch unter den BTM Delinquenten findet man eine relativ hohe ADHS Prävalenz. Die im Rahmen der ADHS auftretende Antisozialität lässt keine wesentlichen Querverbindungen zur Kerngruppe der Psychopathen nach Hare erkennen und kann damit als eigenständige Subgruppe innerhalb der ASP angesehen werden.

Genetic and environmental influences on victims, bullies and bully-victims in childhood

BACKGROUND

Three groups of children are involved in bullying: victims, bullies and bully-victims who are both bullies and victims of bullying. Understanding the origins of these groups is important since they have elevated emotional and behavioural problems, especially the bully-victims. No research has examined the genetic and environmental influences on these social roles.

METHOD

Mother and teacher reports of victimisation and bullying were collected in a nationally representative cohort of 1,116 families with 10-year-old twins. Model-fitting was used to examine the relative influence of genetics and environments on the liability to be a victim, a bully or a bully-victim.

RESULTS

Twelve percent of children were severely bullied as victims, 13% were frequent bullies, and 2.5% were heavily involved as bully-victims. Genetic factors accounted for 73% of the variation in victimisation and 61% of the variation in bullying, with the remainder explained by environmental factors not shared between the twins. The covariation between victim and bully roles (r = .25), which characterises bully-victims, was accounted for by genetic factors only. Some genetic factors influenced both victimisation and bullying, although there were also genetic factors specific to each social role.

CONCLUSIONS

Children's genetic endowments, as well as their surrounding environments, influence which children become victims, bullies and bully-victims. Future research identifying mediating characteristics that link the genetic and environmental influences to these social roles could provide targets for intervention.

A non-additive interaction of a functional MAO-A VNTR and testosterone predicts antisocial behavior

A functional VNTR polymorphism in the promoter of the monoamine oxidase A gene (MAOA-LPR) has previously been shown to be an important predictor of antisocial behavior in men. Testosterone analogues are known to interact with the MAOA promoter in vitro to influence gene transcription as well as in vivo to influence CSF levels of the MAO metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in human males. We examined the possible joint effects of testosterone (measured in CSF) and MAOA-LPR genotype on antisocial personality disorder and scores on the Brown-Goodwin Aggression scale in 95 unrelated male criminal alcoholics and 45 controls. The results confirm that MAOA genotype and CSF testosterone interact to predict antisocial behaviors. The MAOA/testosterone interaction also predicted low levels of CSF MHPG, which tentatively suggests the possibility that the interaction may be mediated by a direct effect on gene transcription. If replicated these findings offer plausible explanations for previous inconsistencies in studies of the relationship between testosterone and male human aggression, as well as for how MAOA genotype may influence aggressive behavior in human males.

Evidence of a gene x environment interaction in the creation of victimization: results from a longitudinal sample of adolescents

A large body of research has revealed that aggressive personality traits and violent criminal behaviors are influenced by genetic factors. Surprisingly, however, no research has been devoted to investigating the potential genetic origins to adolescent victimization. In the current study, the authors address this gap in the literature by using data from the National Longitudinal Study of Adolescent Health (Add Health) to examine whether different variants of the dopamine D2 receptor gene (DRD2) are related to victimization, net of the effects of environmental measures. The results of the multivariate models revealed a significant gene X environment interaction in the creation of victimization for White males. Specifically, DRD2 interacted with delinquent peers to predict victimization. The authors discuss the implications of these findings.