Reciprocal Effects Between Negative Parenting and Children's Callous-Unemotional Traits From Mid to Late Childhood.

OBJECTIVE: The role of negative parenting in the development of callous-unemotional (CU) traits remains unclear. Both negative parenting and CU traits are influenced by genetic and environmental factors. The authors used genetically informed longitudinal cross-lagged models to examine the extent to which reciprocal effects between negative parenting and children's CU traits in mid-to-late childhood are genetic versus environmental in origin. METHODS: In 9,260 twin pairs from the Twins Early Development Study, the authors estimated cross-lagged effects between negative parenting (discipline and feelings) and children's CU traits in mid (ages 7-9) and late (ages 9-12) childhood. RESULTS: CU traits were strongly heritable and stable. Stability was explained largely by genetic factors. The influence of negative parenting on the development of CU traits was small and driven mostly by genetic and shared environmental factors. In mid childhood, the influence of children's CU traits on subsequent negative parenting (i.e., evoked by children's CU traits) was also small and mostly genetic in origin. In late childhood, CU traits showed no effects on negative parental discipline and small effects on negative parental feelings, which reflected mostly shared environmental factors. CONCLUSIONS: In mid-to-late childhood, genetic factors strongly influenced the development of CU traits, whereas environmental effects of negative parenting were small. Negative parenting was also relatively unaffected by CU traits. The small reciprocal effects originated mostly from genetic and shared environmental factors. Therefore, repeated intensive interventions addressing multiple risk factors rather than negative parenting alone may be best positioned to support families of children with CU traits across development.

Promoting Empathy and Affiliation in Relationships (PEAR) study: protocol for a longitudinal study investigating the development of early childhood callous-unemotional traits.

INTRODUCTION: Children with callous-unemotional (CU) traits are at high lifetime risk of antisocial behaviour. Low affiliation (ie, social bonding difficulties) and fearlessness (ie, low threat sensitivity) are proposed risk factors for CU traits. Parenting practices (eg, harshness and low warmth) also predict risk for CU traits. However, few studies in early childhood have identified attentional or physiological markers of low affiliation and fearlessness. Moreover, no studies have tested whether parenting practices are underpinned by low affiliation or fearlessness shared by parents, which could further shape parent-child interactions and exacerbate risk for CU traits. Addressing these questions will inform knowledge of how CU traits develop and isolate novel parent and child targets for future specialised treatments for CU traits. METHODS AND ANALYSIS: The Promoting Empathy and Affiliation in Relationships (PEAR) study aims to establish risk factors for CU traits in children aged 3-6 years. The PEAR study will recruit 500 parent-child dyads from two metropolitan areas of the USA. Parents and children will complete questionnaires, computer tasks and observational assessments, alongside collection of eye-tracking and physiological data, when children are aged 3-4 (time 1) and 5-6 (time 2) years. The moderating roles of child sex, race and ethnicity, family and neighbourhood disadvantage, and parental psychopathology will also be assessed. Study aims will be addressed using structural equation modelling, which will allow for flexible characterisation of low affiliation, fearlessness and parenting practices as risk factors for CU traits across multiple domains. ETHICS AND DISSEMINATION: Ethical approval was granted by Boston University (#6158E) and the University of Pennsylvania (#850638). Results will be disseminated through conferences and open-access publications. All study and task materials will be made freely available on lab websites and through the Open Science Framework (OSF).

Aspectos antissociais na velhice / Les aspects anti-sociaux de la vieillesse / Aspectos antisociales en la vejez / Antissocial aspects in ageing

Resumos Segundo Winnicott, a tendência antissocial tem por etiologia uma deprivação que ocorre quando está se dando a fusão entre os elementos instintuais e motores. A desfusão desses elementos resulta num prejuízo no desenvolvimento criativo das relações objetais e na expressão da agressividade. A tendência antissocial se manifesta através de um transtorno no ambiente, por meio da mentira, do roubo e da destrutividade. Neste artigo, apresento um caso clínico em que surgiram comportamentos antissociais numa pessoa idosa e como se constituiu o setting terapêutico para seu tratamento. Por fim, o texto discute se a etapa da vida que se conhece por velhice, por se apresentar amiúde com decadência física e declínio instintual, não causaria nos indivíduos uma deprivação que se expressaria por meio de múltiplos transtornos, normalmente percebidos como manifestações da mera velhice e que, na verdade, poderiam ser mais bem entendidos como expressão de uma tendência antissocial.

Résumé Selon Winnicott, la tendance antisociale résulte d'une privation qui se produit au moment où s'opère la fusion entre les éléments instinctuels et moteurs. La défusion de ces éléments entraîne une perte dans le développement créatif des relations objectales et dans l'expression de l'agressivité. La tendance antisociale se manifeste par une perturbation de l'environnement, par le mensonge, le vol et la destruction. Cet article présente un cas clinique dans lequel des comportements antisociaux se sont apparu chez une personne âgée et comment s'est constitué le cadre thérapeutique de son traitement. Enfin, le texte propose une réflexion : cette étape de la vie, que l'on nomme vieillesse et qui se présente souvent comme une déchéance physique et un déclin instinctif, ne provoquerait-elle chez les individus une déprivation qui s'exprimerait par de multiples troubles, normalement perçus comme des manifestations de la simple vieillesse mais qui, en fait, pourraient être mieux compris comme l'expression d'une tendance antisociale ?

Resumen Según Winnicott, la tendencia antisocial tiene por etiología una deprivación, que ocurre cuando los elementos instintuales y motores se están fusionando. La escisión entre estos elementos tiene como resultado un perjuicio en el desarrollo creativo de las relaciones objetales y la expresión de agresividad. La tendencia antisocial se manifiesta como una perturbación en el entorno mediante la mentira, el robo y la destructividad. En este artículo se presenta un caso clínico en el que surgieron comportamientos antisociales en una persona mayor y cómo se constituyó el setting terapéutico. Por último, se discute si la etapa de la vida conocida como vejez, por su decadencia física y el deterioro instintual en general, no les causaría a los individuos una deprivación, la cual se expresaría en múltiples desórdenes de la vejez que podrían entenderse como la expresión de una tendencia antisocial.

Abstract According to Winnicott, antisocial tendency etiology is an experience of deprivation that occurs during the fusion between instinctual and motor elements. These elements defusion impairs creative development of object relations and leads to an expression of aggression. In this scenario, the antisocial tendency is expressed by an environmental disorder, through lies, stealing, and destructivity. This article presents a clinical case of antisocial behaviors in an older person, describing the therapeutic setting for the treatment of such condition. Considering that ageing often presents with physical decadence and instinctual decline, it also discusses the association between this life period and a deprivation expressed through multiple disorders that are usually understood as signs of mere senescence but could possibly signify the expression of an antisocial tendency.

Inhibition of ecto-5'-nucleotidase and adenosine deaminase is able to reverse long-term behavioural effects of early ethanol exposure in zebrafish (Danio rerio).

The behavioural impacts of prenatal exposure to ethanol include a lower IQ, learning problems, anxiety and conduct disorders. Several components of the neurochemical network could contribute to the long-lasting effects of ethanol embryonic exposure. Adenosine is an important neuromodulator, that has been indicated to be affected by acute and chronic exposure to ethanol. Here, embryos of zebrafish exposed to 1% ethanol during the developmental stages of gastrula/segmentation or pharyngula exhibited anxiolytic effect, increased aggressiveness, and decreased social interaction. The exposure during pharyngula stage was able to affect all behavioural parameters analysed at 3 months-post fertilization (mpf), while the treatment during gastrula stage affected the anxiety and social interaction parameters. The aggressiveness was the only behavioural effect of early ethanol exposure that lasted to 12 mpf. The use of a specific inhibitor of adenosine production, the inhibitor of ecto-5'-nucleotidase (AMPCP/150 mg/kg), and the specific inhibitor of adenosine degradation, the inhibitor of adenosine deaminase, EHNA (100 mg/kg) did not affect the effects over anxiety. However, AMPCP at 3 mpf, but not EHNA, reversed aggressive parameters. AMPCP also recovered the social interaction parameter at 3 mpf in animals treated in both stages, while EHNA recovered this parameter just in those animals treated with ethanol during the gastrula stage. These results suggest that long-lasting behavioural effects of ethanol can be modulated by intervention on ecto-5'-nucleotidase and adenosine deaminase activities.

Social evaluation and imitation of prosocial and antisocial agents in infants, children, and adults.

The question of whether infants prefer prosocial agents over antisocial agents is contentious. Therefore, the first goal of the present study was to replicate previous findings regarding infants' preference. The second goal was to assess whether infants are more likely to imitate a prosocial agent than an antisocial agent. We tested 9-month-old, 14-month-old, and 4-year-old children. The study used the "opening a box to get a toy" paradigm in which an animal puppet is trying unsuccessfully to open a box and is either helped by a prosocial puppet or hindered by an antisocial puppet. We presented these social events via video, and subsequently administered an imitation task. As an additional control, adults were asked to describe the videos showing the prosocial and antisocial agent. Although most adults were able to identify both agents, the three age groups of children did not prefer the prosocial agent over the antisocial agent, and were not more likely to imitate the prosocial agent. The lack of differences might be explained by methodological issues or by a lack of robustness of the effect.

Endocrine markers of puberty timing and antisocial behaviour in girls and boys.

BACKGROUND: Early puberty is associated with higher than average risk of antisocial behaviour, both in girls and boys. Most studies of such association, however, have focused on psychosocial mediating and moderating factors. Few refer to coterminous hormonal measures. AIM: The aim of this review is to consider the role of hormonal markers as potential mediating or moderating factors between puberty timing and antisocial behaviour. METHOD: A systematic literature search was conducted searching Medline, Embase, Web of Science, Scopus, Psycinfo, Cochrane and Google Scholar. RESULTS: Just eight studies were found to fit criteria, all cross-sectional. Measurements were too heterogeneous to allow meta-analysis. The most consistent associations found were between adrenal hormones-both androgens and cortisol-which were associated with early adrenarche and antisocial behaviours in girls and later adrenarche and antisocial behaviour in boys. CONCLUSIONS: The findings from our review suggest that longitudinal studies to test bidirectional hormone-behaviour associations with early or late puberty would be worthwhile. In view of the interactive processes between hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, integrated consideration of the hormonal end products is recommended.

Callous-Unemotional Traits and Risk of Gun Carrying and Use During Crime.

OBJECTIVE: With the addition of the "with limited prosocial emotions" specifier within the diagnosis of conduct disorder (DSM-5) and of conduct-dissocial disorder (ICD-11) to designate those with elevated callous-unemotional traits, the authors examined the role that callous-unemotional traits play in the risk for gun carrying and gun use during a crime in a sample at high risk for gun violence. METHODS: Male juvenile offenders (N=1,215) from three regions of the United States were assessed after their first arrest and then reassessed every 6 months for 36 months and again at 48 months. Callous-unemotional traits and peer gun carrying and ownership were measured via self-report after the first arrest (i.e., baseline). Gun carrying and use of a gun during a crime were self-reported at all follow-up points. RESULTS: Callous-unemotional traits at baseline increased the frequency of gun carrying and the likelihood of using a gun during a crime across the subsequent 4 years after accounting for other risk factors. Furthermore, callous-unemotional traits moderated the relationship between peer gun carrying and ownership and participant gun carrying, such that only participants low on callous-unemotional traits demonstrated increased gun carrying as a function of their peers' gun carrying and ownership. CONCLUSIONS: This study demonstrates the importance of considering callous-unemotional traits in gun violence research both because callous-unemotional traits increase gun carrying and use in adolescents and because the traits may moderate other key risk factors. Notably, the influence of peer gun carrying and ownership may have been underestimated in past research for the majority of adolescents by not considering the moderating influence of callous-unemotional traits.

The role of monoamine oxidase A in the neurobiology of aggressive, antisocial, and violent behavior: A tale of mice and men.

Over the past two decades, research has revealed that genetic factors shape the propensity for aggressive, antisocial, and violent behavior. The best-documented gene implicated in aggression is MAOA (Monoamine oxidase A), which encodes the key enzyme for the degradation of serotonin and catecholamines. Congenital MAOA deficiency, as well as low-activity MAOA variants, has been associated with a higher risk for antisocial behavior (ASB) and violence, particularly in males with a history of child maltreatment. Indeed, the interplay between low MAOA genetic variants and early-life adversity is the best-documented gene × environment (G × E) interaction in the pathophysiology of aggression and ASB. Additional evidence indicates that low MAOA activity in the brain is strongly associated with a higher propensity for aggression; furthermore, MAOA inhibition may be one of the primary mechanisms whereby prenatal smoke exposure increases the risk of ASB. Complementary to these lines of evidence, mouse models of Maoa deficiency and G × E interactions exhibit striking similarities with clinical phenotypes, proving to be valuable tools to investigate the neurobiological mechanisms underlying antisocial and aggressive behavior. Here, we provide a comprehensive overview of the current state of the knowledge on the involvement of MAOA in aggression, as defined by preclinical and clinical evidence. In particular, we show how the convergence of human and animal research is proving helpful to our understanding of how MAOA influences antisocial and violent behavior and how it may assist in the development of preventative and therapeutic strategies for aggressive manifestations.

[The contribution of forensic neuroscience to psychopathy]. / La psychopathie ­ L'éclairage des neurosciences médicolégales.

Psychopathy is a construct characterized by symptoms of emotional detachment, a lack of empathy, guilt and remorse, irresponsibility and a propensity for impulsive behavior. This article critically evaluates the contribution of structural and functional neuroimaging to the understanding of this personality disorder in North American forensic populations with psychopathic traits. Neuroimaging results are highly variable. They report numerous structural and functional abnormalities that are not limited to the amygdala and the ventromedial prefrontal cortex but include the striatum, hippocampus, and uncinate fasciculus. These brain abnormalities underlie an attenuated emotion processing functioning (but not an absence) and aversion to negative and threats signals, reinforcement learning, representation of rewards and modulation of attention that have an impact in decision-making, caring for others, and moral judgment. It is important to note that the neuroanatomical, neurofunctional, and behavioral differences between individuals with high psychopathic traits and those with low traits are highly heterogeneous and of degree rather than of nature.

[Toxoplasmosis and behavioural changes (French translation of the article)]. / Toxoplasmose et modifications du comportement humain.

Nearly one-third of the planet's population is affected by T. gondii infection. In ophthalmology, toxoplasmosis is even considered to be the most common cause of posterior uveitis of infectious origin. Humans are only an intermediate host, and T. gondii needs to infect cats for its sexual reproduction. All the elements increasing the risk of predation by the definitive host are then favourable to the parasite. Numerous experimental animal model studies have shown that T. gondii infection is associated with predatory risk behaviours such as an attraction of infected mice to cat urine. Infection with the parasite is associated with a demethylation of the promoters of certain genes in the cerebral amygdala of the intermediate hosts, modifying dopaminergic circuits associated with fear. Similarly, T. gondii has been linked to behavioural changes in humans. Toxoplasma infection is classically associated with the frequency of schizophrenia, suicide attempts or "road rage." A more recent study shows that toxoplasma infection prevalence was a consistent, positive predictor of entrepreneurial activity. Fear of failure would be less important in infected individuals, who are more willing than others to start their own business. These elements shed interesting light on behaviours and their possible relationship with toxoplasmosis, which is generally considered benign in adults.

Differences in attachment dimensions and reflective functioning between traumatized juvenile offenders and maltreated non-delinquent adolescents from care services.

BACKGROUND: Adverse childhood experiences, especially maltreatment, are regarded as significant risk factors for the development of antisocial behavior in adolescence. However, possible correlates are still to be investigated after considering the history of criminal records and the experience of institutionalization. OBJECTIVE: In this study, differences in attachment anxiety and avoidance, and reflective functioning (RF) between traumatized incarcerated juvenile offenders and non-delinquent adolescents institutionalized in child services because of domestic violence were examined. PARTICIPANTS, SETTING AND METHOD: Forty-two juvenile offenders (Nfemale = 19) and 43 inmates of institutions for adolescents without parental care (Nfemale = 20) with the history of trauma filled in the childhood trauma and attachment dimensions questionnaires, and were scored on the Reflective Functioning Scale. Groups were matched on age and education. RESULTS: Results indicate that both groups reported equally high levels of attachment anxiety and avoidance. Male juvenile offenders had lower scores on reflective functioning than both female convicted minors (B = 1.06; Odds Ratio = 2.88; Nagelkerkes R2 = 45) and non-delinquent adolescents of both genders (B = -.65; Odds Ratio = .52; Nagelkerkes R2 = 42). In comparison to non-convicted males, male offenders also had higher scores on the control scale of idealization (B = .35; Odds Ratio = 1.42; Nagelkerkes R2 = 42). No differences between females with and without a history of crimes were found. CONCLUSIONS: Results indicate a need for building RF in both traumatized samples, especially in male delinquents, and encourage further research in females.

Psychopathy in Adolescence: Causes, Traits and Risk Behaviours.

Psychopathy is a personality disorder defined by a specific set of behaviours and personality traits evaluated as negative and socially harmful. The modern conception of Psychopathy was introduced by Clerckley in "Mask of Sanity" (1941), and refined by Hare with the construction of the PCL (1980, 1991), a gold standard instrument for the evaluation of the disorder. Manipulation, deception, grandeur, emotional superficiality, lack of empathy and remorse, impulsive and irresponsible lifestyle, persistent violation of social norms and expectations (Cleckley 1976, Hare 2003) are some behavioural aspects that characterize psychopathic subjects. With this work we intend to study in depth the causes, the traits, in particular the so-called callous-unemotional and risk factors that lead a teenager to become a psychopathic subject. The diagnostic tools useful for the assessment and for the possibilities of intervention that can be put into practice will also be described.

Pediatric traumatic brain injury and antisocial behavior: are they linked? A systematic review.

Purpose: Despite growing evidence supporting a link between pediatric traumatic brain injury (TBI) and antisocial behavior, little work has rigorously evaluated this. This review aimed to explore systematically previous literature on the association between TBI before the age of 19 and severe behavioral problems such as violence, aggression and assault. Methods: All articles published from 1990 to 2018 were searched using four major databases, alongside manual searching and cross-referencing. Results: Sixteen articles met the eligibility criteria. Overall, they supported an association between pediatric TBI and antisocial behavior. Factors were identified that might influence this link, such as, for example, TBI severity and substance use. Conclusions: The review identified several issues in the current literature, highlighting key areas for improvement. It is imperative that more attention is paid to gathering detailed information regarding the temporal sequencing of events and TBI severity; evaluating the contribution of biopsychosocial variables co-occurring with TBI and antisocial behavior; disentangling which outcomes are specific to TBI versus any injury. The review has implications for the health and justice systems; regardless of whether TBI is the cause versus a contributing factor to antisocial behavior, increased awareness of their association could lead to more comprehensive assessments, tailored interventions and effective sentencing.

The etiology of antisocial personality disorder: The differential roles of adverse childhood experiences and childhood psychopathology.

Antisocial Personality Disorder (ASPD) is a severe personality disorder with robust associations with crime and violence, but its precise etiology is unknown. Drawing on near-population of federal correctional clients in the Midwestern United States, the current study examined antecedent background factors spanning adverse childhood experiences and childhood psychopathology. Greater adverse childhood experiences were associated with ASPD diagnosis with physical abuse showing associations with ASPD symptoms and sexual abuse with lifetime diagnosis for ASPD. Conduct Disorder was strongly linked to ASPD; however, Oppositional Defiant Disorder and ADHD had null associations. Given the role of environmental factors in the development of ASPD, greater criminological attention should be devoted to understanding how assorted forms of abuse and neglect coupled with childhood psychopathology contribute to ASPD especially given its linkages to severe criminal offending.

Relationships between Early Life Victimization, Antisocial Traits, and Sexual Violence: Executive Functioning as a Mediator.

Few research studies examine how the relationship between trauma and executive functioning can influence sexual violence among youth. Knight and Sims-Knight (2004) proposed a Developmental Etiological Theory (DET) connecting early life physical and sexual victimization to sexual violence via antisocial traits. Drawing from research that identifies a link between early life victimization and executive functioning, this study tests an adaptation to the DET by including executive functioning as an intervening factor. Using data on adolescents adjudicated of sexual and non-sexual crimes in a western state (N = 200), multiple structural equation models tested direct and indirect relationships between early life sexual, physical victimization, and other adversity, four differential forms of executive functioning, callousness, and sexual violence. Results revealed statistically significant direct pathways between variables of interest and a multi-meditational effect of certain forms of executive functioning and callousness in the relationship between victimization and sexual violence. Treatment and research implications are discussed.

Is Female Psychopathy Linked with Child Abuse? An Empirical Investigation using a Person-Centered Approach.

Childhood abuse is associated with increased psychopathic features among girls, but most prior research is based on data from correctional samples of female delinquents and less is known about how specific forms of childhood abuse affect specific features of psychopathy. Using a school-based community sample of 696 girls aged 9-17 years from Barbados and Grenada, the current study examined latent profiles of psychopathic personality traits and their associations with physical, emotional, and sexual abuse. Latent profile analysis (LPA) revealed four distinct psychopathy groups among girls, including a 'low psychopathy' group (41.9% of girls), 'high psychopathy' group (4.8%), 'high interpersonal manipulation and egocentricity' group (37.4%), and a 'moderate psychopathy' group (16%). There was considerable evidence of physical abuse, emotional abuse, and sexual abuse among participants. Sexual abuse was associated with a 116% increased likelihood of membership in the high psychopathy group and a 57% increased likelihood of membership in the high interpersonal manipulation and egocentricity group. These results indicate that sexual abuse is a powerful distal factor in the development of psychopathic personality functioning, especially more severe variants.

Genetic and environmental influences on disinhibition, boldness, and meanness as assessed by the triarchic psychopathy measure in 19-20-year-old twins.

BACKGROUND: The Triarchic Psychopathy Measure (TriPM) provides Disinhibition, Boldness, and Meanness scales for assessing the three trait domains of the triarchic model. Here we examined the genetic and environmental etiology of these three domains, including evaluation of potential sex differences. METHODS: A total of 1016 men and women ages 19-20 years were drawn from the University of Southern California Risk Factors for Antisocial Behavior twin study. RESULTS: Scores for the three TriPM scales were correlated to differing degrees, with the strongest phenotypic correlation between Disinhibition and Meanness. No sex differences were found in the genetic and environmental influences underlying these three domains, suggesting that the same genes and life experiences contribute to these traits in young men and women. For TriPM Disinhibition and Boldness, genetic factors explained about half or less of the variance, with the rest of the variance being explained by non-shared environmental factors. For TriPM Meanness, on the other hand, genetic, shared environmental, and non-shared environmental factors accounted for the variance. The phenotypic correlation between Disinhibition and Meanness was explained in part by common genes (26%), with the remainder attributable about equally to common shared (39%), and non-shared environmental influences (35%). CONCLUSIONS: These findings contribute to our understanding of psychopathic personality traits by demonstrating the importance of heritable factors for disinhibition and boldness facets of psychopathy, and the importance of shared environmental influences for the meanness facet.

Current Knowledge on Gene-Environment Interactions in Personality Disorders: an Update.

PURPOSE OF REVIEW: We review the existing literature on gene-environment interactions (G×E) and epigenetic changes primarily in borderline personality disorder (BPD) but also in antisocial, schizotypal, and avoidant personality disorders. RECENT FINDINGS: Research supports that susceptibility genes to BPD or its underlying traits may be expressed under certain environmental conditions such as physical or childhood sexual abuse. Epigenetic modifications of neurodevelopment- and stress-related genes are suggested to underlie the relationship between early life adversary and borderline personality disorder. Only limited studies have investigated the role of gene-environment interactions and epigenetic changes in the genesis of antisocial, schizotypal, and avoidant personality disorders. Considering the lack of pharmacological treatment for most personality disorders, the emerging evidence on the critical role of G×E and epigenetic changes in the genesis of personality disorders could help develop more biologically oriented therapeutic approaches. Future studies should explore the potential of this new therapeutic dimension.

The interplay of gender, parental behaviors, and child maltreatment in relation to psychopathic traits.

Many studies have reported an effect of childhood maltreatment and parenting behavior with the future development of psychopathic traits. However, there is a limited amount of research on parenting behavior and adult psychopathic traits as possible identifiers of childhood maltreatment. The aim of this study is three-fold (1) identify specific parenting behaviors and adult psychopathic traits that predict forms of childhood maltreatment, (2) explore gender differences, and (3) expand on other studies on psychopathy by focusing on a representative sample of the community. There are significant associations between recalled childhood maltreatment and parenting behavior, and psychopathic traits. Parental rejection was the most recurrent predictor of childhood maltreatment with a significant positive relation to almost all its forms. Paternal overprotection was positively associated with sexual abuse, while the opposite was true for maternal overprotection. Psychopathic traits displayed in adulthood were also strong indicators of childhood maltreatment; females with high levels of boldness were more likely to have experienced sexual abuse in childhood, and those high in disinhibition were more likely to have experienced physical neglect and sexual abuse. While males were generally higher in terms of psychopathic traits, females reported more childhood abuse and negative parental behaviors. These findings provide support for using parenting behavior and psychopathic traits as markers of childhood maltreatment.

Gene-environment interaction of monoamine oxidase A in relation to antisocial behaviour: current and future directions.

Since the pioneering finding of Caspi and co-workers in 2002 that exposure to childhood maltreatment predicted later antisocial behaviour (ASB) in male carriers of the low-activity MAOA-uVNTR allele, frequent replication studies have been published. Two meta-analyses, one in 2006 and the other in 2014, confirmed the original findings by Caspi and co-workers. In the present paper, we review the literature, note some methodological aspects of candidate gene-environment interaction (cG×E) studies and suggest some future directions. Our conclusions are as follows. (1) The direction of the effect in a cG×E model may differ according to the positive and negative environmental background of the population. (2) There is a predictor-intersection problem such that when measuring one type of maltreatment in a person, other kinds of maltreatment often co-occur. Other forms of abuse are implicitly considered in statistical models; therefore, it is difficult to draw conclusions about the effects of timing and the severity of different forms of stressful life events in relation to ASB. (3) There is also an outcome-intersection problem because of the major intersection of ASB and other forms of mental health problems. It is likely that the G×E with MAOA is related to a common unmeasured factor. (4) For the G×E model, in which the effect of the gene on the outcome variable is dependent on other predictor variables, theoretically, hypothesis-driven statistical modelling is needed.