[Show abstract][Hide abstract] ABSTRACT: This study examined sibling influence over gambling involvement and delinquency in a sample of 628 twins (151 male dyads, 163 female dyads). Self-reports of gambling involvement and delinquency were collected for each twin at ages 13, 14 and 15 years. Results revealed evidence of between-twin influence. Higher levels of an adolescent's delinquency predicted an increase in his or her co-twin's delinquency from age 13 to age 14 and from age 14 to age 15. In contrast, gambling behavior was unaffected by the co-twin's gambling involvement. Within-twins, higher initial levels of delinquency predicted a subsequent increase in gambling behavior from age 13 to age 14 and again from age 14 to age 15, and higher initial levels of gambling involvement predicted an increase in delinquency from age 14 to age 15. Between and within siblings effects are discussed in light of the scant literature on (a) sibling influence on gambling, and (b) the links between gambling and delinquency.
[Show abstract][Hide abstract] ABSTRACT: In this 16-year longitudinal study, a new trajectory estimation approach was used to verify whether the developmental course of childhood inattention significantly predicted functional impairment. A rising childhood inattention trajectory significantly predicted graduation failure (OR: 1.76 [1.32-2.34]) independently of averaged inattention levels. Rising inattention is, in itself, important for prognosis.
[Show abstract][Hide abstract] ABSTRACT: This study examined the genetic and environmental architecture of early gambling involvement and substance use to determine whether genetic or environmental factors that contribute to substance use also put young adolescents at risk for early involvement in gambling. Self-reports of substance use and gambling involvement were collected at age 13 years from 279 Monozygotic and Dizygotic twin pairs. Univariate ACE modeling revealed that genetic and nonshared environmental factors almost equally accounted for gambling involvement, with no contribution from shared environmental factors. In contrast, both shared and nonshared environmental factors played important roles in substance use; the contribution of genetic factors was also substantial. Bivariate analyses identified a significant, albeit modest, overlap between the genetic influence on gambling involvement and the genetic influence on substance use. The results shed light on the etiology of early gambling involvement and substance use, suggesting that preventive interventions targeting common risk factors may also need to be complemented by modules that are specific to each behavior.
[Show abstract][Hide abstract] ABSTRACT: Several authors consider high and frequent conflicts between friends during childhood as a serious risk for subsequent conduct problems such as generalized physical aggression toward others (e.g., Kupersmidt, Burchinal, & Patterson, 1995; Sebanc, 2003). Although it seems logical to assume that friendship conflict could have some negative consequences on children's behaviors, some scholars have suggested that a certain amount of conflict between friends may actually promote social adjustment (e.g., Laursen & Pursell, 2009). The aim of this study was to investigate the role of friendship conflict in regard to the development of generalized physical aggression toward others in the early school years (i.e., from kindergarten to Grade 1), as well as the moderating role of relational (i.e., shared positive affect and dyadic conflict resolution skills) and personal (i.e., children's sex and genetic liability for aggression) characteristics in this context. The sample included 745 twins assessed through teacher, peer, child, and friend ratings in kindergarten and Grade 1. Friendship conflict in kindergarten was linearly related to an increase in boys' but not girls' generalized physical aggression. However, shared positive affect and conflict resolution skills mitigated the prospective associations between friendship conflict and generalized physical aggression. These results were independent of children's sex, genetic risk for physical aggression, and initial levels of generalized physical aggression in kindergarten. Fostering a positive relationship between friends at school entry may buffer against the risk associated with experiencing friendship conflict. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
[Show abstract][Hide abstract] ABSTRACT: Using a genetically informed twin design, this study examined (a) whether, in line with gene-environment correlation (rGE), a genetic disposition for anxiety puts children at risk of being victimized by a close friend or by other peers, and (b) whether, in line with gene-environment interaction (GxE), victimization by a close friend or by other peers moderates the expression of a genetic disposition for anxiety. Participants were 268 monozygotic and dizygotic twin pairs (MZ males = 71, MZ females = 80, DZ males = 56, DZ females = 61; 87% of European descent) assessed via questionnaires in Grade 8 (M age = 14.06 years, SD = 3.60). Participants reported about their victimization by a close friend and by other peers and their anxiety level. Victimization by a close friend and victimization by other peers were uncorrelated. In line with rGE, genetic factors related to anxiety predicted victimization by other peers, whereas victimization by a close friend was not predicted by heritable characteristics. Moreover, in line with a suppression process of GxE, victimization by other peers reduced the role of genetic factors in explaining interindividual differences in anxiety. In contrast, in line with a diathesis-stress process of GxE, victimization by a close friend fostered the expression of a genetic disposition for anxiety. Victimization by a close friend seems to happen to adolescents regardless of their personal, heritable characteristics. If it does occur, however, it is a source of distress mostly for youth with a genetic vulnerability for anxiety.
[Show abstract][Hide abstract] ABSTRACT: Peer antisocial behavior robustly predicts adolescents' own behavior but not all adolescents are equally vulnerable to their peers' influence and genetic factors may confer vulnerability. This study used data of n = 3081 adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine whether BDNF, a polymorphism that affects psychological functioning, moderates the association between affiliation with aggressive peers at age 10 and own aggression at age 15. A significant gene-environment interaction was found, where those who affiliated with aggressive peers in childhood showed increased risk for being aggressive in adolescence if they carried the BDNF met-met variant compared to val-val carriers. Our findings underline the importance of both biological and social factors for adolescent development.
Journal of Research on Adolescence 03/2014; 24(1):177-185. · 1.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background. Physical aggression (PA) tends to have its onset in infancy and to increase rapidly in frequency. Very little is known about the genetic and environmental etiology of PA development during early childhood. We investigated the temporal pattern of genetic and environmental etiology of PA during this crucial developmental period.
Psychological Medicine 01/2014; · 5.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: High frequency of physical aggression is the central feature of severe conduct disorder and is associated with a wide range of social, mental and physical health problems. We have previously tested the hypothesis that differential DNA methylation signatures in peripheral T cells are associated with a chronic aggression trajectory in males. Despite the fact that sex differences appear to play a pivotal role in determining the development, magnitude and frequency of aggression, most of previous studies focused on males, so little is known about female chronic physical aggression. We therefore tested here whether or not there is a signature of physical aggression in female DNA methylation and, if there is, how it relates to the signature observed in males.
Methylation profiles were created using the method of methylated DNA immunoprecipitation (MeDIP) followed by microarray hybridization and statistical and bioinformatic analyses on T cell DNA obtained from adult women who were found to be on a chronic physical aggression trajectory (CPA) between 6 and 12 years of age compared to women who followed a normal physical aggression trajectory. We confirmed the existence of a well-defined, genome-wide signature of DNA methylation associated with chronic physical aggression in the peripheral T cells of adult females that includes many of the genes similarly associated with physical aggression in the same cell types of adult males.
This study in a small number of women presents preliminary evidence for a genome-wide variation in promoter DNA methylation that associates with CPA in women that warrant larger studies for further verification. A significant proportion of these associations were previously observed in men with CPA supporting the hypothesis that the epigenetic signature of early life aggression in females is composed of a component specific to females and another common to both males and females.
PLoS ONE 01/2014; 9(1):e86822. · 3.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to test the impact of two interventions designed to promote social competence in aggressive kindergartners. A sample of 182 aggressive students (69% boys) were randomly assigned to three conditions: a) an intervention promoting social competence in classrooms (PSC); b) PSC intervention combined with a dyadic peer intervention (PSC + DPI), and c) control. The impact of these interventions were assessed using parent and teacher ratings, direct observations of behaviours and individual interviews with the children. After the end of the interventions, children in the two experimental conditions showed better social problem solving skills compared to control children. Direct observations indicated that boys in the PSC condition and girls in the PSC + DPI condition were more incline to propose an idea to their peers. A marginal increase is also found for cooperation in the two experimental conditions. Overall, the impact of the PSC + DPI condition is not superior to the PSC only condition. These findings are discussed in the context of other similar prevention programs and the characteristics of effectiveness studies. (PsycINFO Database Record (c) 2014 APA, all rights reserved)
Canadian Journal of Behavioural Science / Revue canadienne des sciences du comportement. 01/2014; 46(2):301.
[Show abstract][Hide abstract] ABSTRACT: Chronic physical aggression (CPA) is characterized by frequent use of physical aggression from early childhood to adolescence. Observed in approximately 5% of males, CPA is associated with early childhood adverse environments and long-term negative consequences. Alterations in DNA methylation, a covalent modification of DNA that regulates genome function, have been associated with early childhood adversity.
To test the hypothesis that a trajectory of chronic physical aggression during childhood is associated with a distinct DNA methylation profile during adulthood.
We analyzed genome-wide promoter DNA methylation profiles of T cells from two groups of adult males assessed annually for frequency of physical aggression between 6 and 15 years of age: a group with CPA and a control group. Methylation profiles covering the promoter regions of 20 000 genes and 400 microRNAs were generated using MeDIP followed by hybridization to microarrays.
In total, 448 distinct gene promoters were differentially methylated in CPA. Functionally, many of these genes have previously been shown to play a role in aggression and were enriched in biological pathways affected by behavior. Their locations in the genome tended to form clusters spanning millions of bases in the genome.
This study provides evidence of clustered and genome-wide variation in promoter DNA methylation in young adults that associates with a history of chronic physical aggression from 6 to 15 years of age. However, longitudinal studies of methylation during early childhood will be necessary to determine if and how this methylation variation in T cells DNA plays a role in early development of chronic physical aggression.
PLoS ONE 01/2014; 9(4):e89839. · 3.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Using a genetically informed design based on 197 Monozygotic and Dizygotic twin pairs assessed in grade 4, this study examined 1) whether, in line with a gene-environment correlation (rGE), a genetic disposition for physical aggression or relational aggression puts children at risk of being victimized by their classmates, and 2) whether this rGE is moderated by classroom injunctive norm salience in regard to physical or relational aggression. Physical aggression and relational aggression, as well as injunctive classroom norm salience in regard to these behaviors, were measured via peer nominations. Peer victimization was measured via self-reports. Multi-Level Mixed modeling revealed that children with a genetic disposition for either aggressive behavior are at higher risk of being victimized by their peers only when classroom norms are unfavourable toward such behaviors. However, when classroom injunctive norms favor aggressive behaviors, a genetic disposition for physical or relational aggression may actually protect children against peer victimization. These results lend further support to the notion that bullying interventions must include the larger peer context instead of a sole focus on victims and bullies.
Journal of Abnormal Child Psychology 10/2013; · 3.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Associating with substance using peers is generally considered as one of the most important predictors of adolescent substance use. However, peer association does not affect all adolescents in the same way. To better understand when and under what conditions peer association is most linked with adolescent substance use (SU), this review focuses on the factors that may operate as moderators of this association. The review highlighted several potential moderators reflecting adolescents' individual characteristics (e.g., pubertal status, genes and personality), peer and parental factors (e.g., nature of relationships and parental monitoring), and contextual factors (e.g., peer, school and neighborhood context). As peer association is a broad concept, important methodological aspects were also addressed in order to illustrate how they can potentially bias interpretation. Taking these into account, we suggest that, while the effects of some moderators are clear (e.g., parental monitoring and sensation seeking), others are less straightforward (e.g., neighborhood) and need to be further examined. This review also provides recommendations for addressing different methodological concerns in the study of moderators, including: the use of longitudinal and experimental studies and the use of mediated moderation. These will be key for developing theory and effective prevention.
[Show abstract][Hide abstract] ABSTRACT: This study examined whether (a) a genetic disposition for physical health problems increases the risk of peer victimization and (b) peer victimization interacts with genetic vulnerability in explaining physical health problems.
Participants were 167 monozygotic and 119 dizyogtic twin pairs. Physical symptoms were assessed in early childhood and early adolescence. Peer victimization was assessed in middle childhood.
Genetic vulnerability for physical health problems in early childhood was unrelated to later peer victimization, but genetic vulnerability for physical health problems during early adolescence increased the risk of victimization. Victimization did not interact with genetic factors in predicting physical symptoms. Environmental, not genetic, factors had the greatest influence on the development of physical symptoms in victims.
Genetic vulnerability for physical health problems in early adolescence increases the risk of peer victimization. Whether victims suffer a further increase in physical symptoms depends on the presence of protective environmental factors.
Journal of Pediatric Psychology 10/2013; · 2.91 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study used a genetically informed design to assess the effects of friends' and nonfriends' reticent and dominant behaviors on children's observed social reticence in a competitive situation. Potential gene-environment correlations (rGE) and gene-environment interactions (GxE) in the link between (a) friends' and nonfriends' behaviors and (b) children's social reticence were examined. The sample comprised 466 twin children (i.e., the target children), each of whom was assessed in kindergarten together with a same-sex friend and two nonfriend classmates of either sex. Multilevel regression analyses revealed that children with a genetic disposition for social reticence showed more reticent behavior in the competitive situation and were more likely to affiliate with reticent friends (i.e., rGE). Moreover, a higher level of children's reticent behavior was predicted by their friends' higher social reticence (particularly for girls) and their friends' higher social dominance, independently of children's genetic disposition. Children's social reticence was also predicted by their nonfriends' behaviors. Specifically, children were less reticent when male nonfriends showed high levels of social reticence in the competitive situation, and this was particularly true for children with a genetic disposition for social reticence (i.e., GxE). Moreover, children genetically vulnerable for social reticence seemed to foster dominant behavior in their female nonfriend peers (i.e., rGE). In turn, male nonfriends seemed to be more dominant as soon as the target children were reticent, even if the target children did not have a stable genetic disposition for this behavior. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
[Show abstract][Hide abstract] ABSTRACT: This investigation utilized two-part growth modeling and cross-lagged panel analysis to examine the predictive function of parenting and teacher-child relationship on the likelihood of children showing problems with parent-rated physical aggression, and on the severity of problems, for 374 children followed from pre-kindergarten and first grade. Two-part modeling found that teacher-child relationship did not differentiate children who did or did not show aggression problems; parental warmth did, but only in pre-kindergarten. For children who showed problems with aggression, parental warmth predicted the severity of those problems in pre-kindergarten, and teacher-child conflict predicted severity of aggression problems in first grade. Cross-lagged panel analyses similarly indicated that parental warmth in pre-kindergarten predicted aggression in kindergarten, but that kindergarten teacher-child conflict predicted subsequent higher aggression in first grade. Shifts in the importance of specific microsystems over time on children’s social development (chronosystem) are discussed, as are the implications for teachers and preservice teacher training.
[Show abstract][Hide abstract] ABSTRACT: Objectif : La Substance Use Risk Profile Scale (SURPS) est un instrument de dépistage des caractéristiques de personnalité qui représentent un risque pour le développement d'une consommation problématique de substances. La SURPS comporte 23 items évaluant 4 dimensions et permet aux intervenants en santé mentale de mieux cibler la prévention. La SURPS a été validée au Canada anglais, au Royaume-Uni, en Chine et au Sri Lanka; l'objectif de cette étude est de valider une traduction française de la SURPS pour des adolescents francophones québécois, en plus d'en tester la sensibilité dans une population clinique. Méthode : Deux cent deux jeunes de 15 ans d'un échantillon communautaire ont répondu à la SURPS et à des mesures de la personnalité et de l'utilisation de substances. La cohérence interne, la solution factorielle et la validité concomitante de l'échelle ont été évaluées. Quarante adolescents (âge moyen de 15,7 ans) présentant un diagnostic psychiatrique ont également répondu à la SURPS et les scores ont été comparés aux normes de l'échantillon communautaire. Résultats : La traduction française de la SURPS démontre une bonne cohérence interne ainsi qu'une solution factorielle à 4 facteurs semblable à la version originale. Ses 4 sous-échelles ont une bonne validité concomitante. De plus, 3 de ses sous-échelles sont corrélées avec des mesures relatives à la consommation de substances psychoactives. Finalement, 95 % des participants de l'échantillon clinique ont été identifiés à risque selon les scores limites de la SURPS. Conclusion : La version française de la SURPS paraît être une mesure valide et sensible pouvant être utilisée auprès d'une population adolescente, québécoise et francophone.
Canadian journal of psychiatry. Revue canadienne de psychiatrie 09/2013; 58(9):538-545. · 2.48 Impact Factor