[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: 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
[show abstract][hide abstract] ABSTRACT: Adolescent substance use is associated with both earlier childhood behavioural problems and serious lifetime addiction problems later in life.
To examine whether, and through which mechanisms, targeting risk factors in early childhood prevents substance use across adolescence.
Disruptive kindergarten boys (n = 172) living in Montreal were randomly allocated to a preventive intervention and a control condition. The intervention was delivered over 2 years (7-9 years of age) with two main components: (a) social and problem-solving skills training for the boys; and (b) training for parents on effective child-rearing skills.
Adolescent substance use, up to 8 years post-intervention, was reduced in those who received the intervention (d = 0.48-0.70). Of most interest, the intervention effects were explained partly by reductions in impulsivity, antisocial behaviour and affiliation with less deviant peers during pre-adolescence (11-13 years).
Adolescent substance use may be indirectly prevented by selectively targeting childhood risk factors that disrupt the developmental cascade of adolescent risk factors for substance use.
The British journal of psychiatry: the journal of mental science 08/2013; · 6.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: Most research linking early pubertal development to substance use has focused on the effects of pubertal timing (age at which a certain stage of pubertal development is reached or pubertal status at a particular age-related to the maturation disparity hypothesis), but little research has focused on pubertal tempo (rate of growth through pubertal stages-related to the maturation compression hypothesis). However, both timing and tempo have not only been identified as important components of pubertal development, with different predictors, but have also been shown to be independently associated with other adolescent psychopathologies. Using latent growth-curve modeling, this study examined how pubertal status at age 12 and pubertal tempo (between 11 and 13 years) related to substance use from 15 to 16 years in boys from low socioeconomic backgrounds (N = 871). Results showed that both pubertal status at age 12 and tempo were significant predictors of increased levels of substance use and problems in mid to late adolescence. In an attempt to identify mechanisms that may explain the association between pubertal development and substance use it was found that sensation seeking partially mediated the association between pubertal status at age 12 and substance use behaviors. Impulse control was found to moderate the association sensation seeking had with marijuana use frequency, with high sensation-seeking scores predicting higher marijuana use frequency only at low levels of impulse control. These findings highlight the importance of considering multiple sources of individual variability in the pubertal development of boys and provide support for both the maturational disparity and compression hypotheses. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
Journal of Abnormal Psychology 08/2013; 122(3):782-96. · 4.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: The study examined whether reciprocal friendship quantity or quality can mitigate genetic vulnerability for depression symptoms in children. The sample comprised 168 monozygotic twin pairs and 126 same-sex dizygotic twin pairs assessed in Grade 4 (mean age = 10.04 years). Friendship participation was measured via reciprocal nominations of close friendships within the classroom. Friendship quality was measured through self-reports. Depression symptoms were measured through teacher and peer reports. Genetic vulnerability for depression symptoms was unrelated to friendship participation or the number of reciprocal friends, but it was negatively related to positive friendship quality. In line with gene-environment interaction, genetic risk effects on depression symptoms were mitigated in girls who had at least one close reciprocal friend. In boys, only moderate main effects of genetic vulnerability and friendship participation were found but no interaction between them. However, among boys with at least one reciprocal friend, a greater number of friends was related to fewer depression symptoms whereas no cumulative effect of friendship was found for girls. Finally, positive friendship quality was related to fewer depression symptoms in girls and boys even when controlling for genetic risk. The findings emphasize the importance of teaching social interactional skills that promote high-quality friendship relations to help prevent the development of depression symptoms in children.
Development and Psychopathology 05/2013; 25(2):277-89. · 4.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: The experience of low socioeconomic position in childhood may increase risk for adult cardiovascular disease above and beyond the effects of current socioeconomic position. One limitation of most previous research is that childhood socioeconomic position was assessed retrospectively. METHODS: Measures of ambulatory blood pressure, heart rate, and heart rate variability were obtained from 110 young men (22 years) who were enrolled in a long-term study of child development at age 6. RESULTS: Men who had lower childhood socioeconomic position had smaller decreases in systolic blood pressure (SBP) during sleep independent of current education, daytime SBP, and body mass index (BMI). They also displayed smaller decreases in low-frequency heart rate variability during sleep. Twenty-four-hour SBP was negatively associated with childhood socioeconomic position independent of current education and BMI. CONCLUSIONS: While the mechanisms are unclear, childhood socioeconomic position may influence blood pressure in early adulthood independent of current life circumstances.
Annals of Behavioral Medicine 04/2013; · 4.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: Oppositional and defiant behavior (ODB) problems are among the most important behavior problems in school children. Understanding their trajectories during elementary school and conditional risk factors at school entry is essential for implementing effective preventive and corrective interventions. Behavior problems of a population sample (958 boys, 971 girls) attending public schools were assessed annually by teachers. Three groups were identified: High Opposition (HO; 14.5%), Moderate Opposition (MO; 37.5%), and Low Opposition (LO; 48.0%). Children on the HO trajectory were found to be different from those on the MO and LO trajectories for numerous kindergarten risk factors: a) they tended to be boys with high family adversity; b) their mothers reported low warmth and high control; c) teachers rated them high on physical aggression, opposition, hyperactivity and low anxiety. Children who are likely to have chronic ODB throughout the elementary school years can be identified in kindergarten. Preventive interventions at school entry could probably help these children.
Australian Journal of Educational and Developmental Psychology 04/2013; 3:234-243.
[show abstract][hide abstract] ABSTRACT: Objective: To examine associations of teacher-rated conduct problems (CP) and hurtful and uncaring behaviours (HUB) at age 6 and 10 with criminal convictions up to age 24 among 1593 males and 1423 females, and to determine whether aggressive behaviour at age 12 mediated the associations of CP and HUB with criminal convictions. Method: Teachers assessed HUB and CP at ages 6 and 10 and ratings above the 90th percentile at each age and within each sex were used to assign participants to 1 of 4 groups. Teachers assessed proactive, reactive, indirect, and verbal aggression at age 12. Juvenile and adult criminal records were obtained. Results: High CP and HUB males, aged 6, were 4 times more likely than males with lower ratings to acquire convictions for violent crimes and 5 times more likely to acquire convictions for nonviolent crimes by age 24. High HUB and CP females, aged 6, were 5 times more likely than females with lower ratings to have a conviction for a nonviolent offence by age 24. Among males, both aged 6 and 10, high HUB without CP were associated with elevations at risk of convictions for violent and nonviolent crimes, while among females the elevations at risk were limited to convictions for nonviolent crimes. Different types of aggressive behaviour mediated associations of high HUB and CP with subsequent criminal convictions, but not the association of HUB without CP and crime. Conclusions: Teachers in elementary schools rated behaviours that, from age 6 onward, significantly predicted criminal convictions into early adulthood.
Canadian journal of psychiatry. Revue canadienne de psychiatrie 03/2013; 58(3):143-50. · 2.48 Impact Factor