This study aimed to identify joint trajectories of peer cyber and traditional victimization from ages 13 to 17 and individual, family, peer, and school risk factors associated with group membership. The sample was composed of 1,194 adolescents (54.2% girls). Cyber and traditional victimization were assessed at ages 13, 15, and 17. The results…

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…

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…

Using a genetically informed design, this study examined the additive and interactive effects of genetic risk, personal peer victimization experiences, and peer victimization experienced by others on children's aggression and depression symptoms. Of major interest was whether these effects varied depending on whether or not the victimized others…

This study used a genetically controlled design to examine the direction and the magnitude of effects in the over-time associations between perceived relationship quality with mothers and adolescent maladjustment (i.e., depressive symptoms and delinquency). A total of 163 monozygotic (MZ) twins pairs (85 female pairs, 78 male pairs) completed…

Positive friendships have been related to decreasing levels of children's physical aggression over time. While this evidence calls for interventions aimed at helping children build good-quality friendships, tests of causality through experimental manipulations are still needed. The goal of this study was to examine whether an intervention aimed to…

This study examined whether clique isolation predicted an increase in depressive symptoms and whether this association was mediated by loneliness and perceived social acceptance in 310 children followed from age 11-14 years. Clique isolation was identified through social network analysis, whereas depressive symptoms, loneliness, and perceived…

Background: The phenotypic and genetic associations between decoding skills and ADHD dimensions have been documented but less is known about the association with reading comprehension. The aim of the study is to document the phenotypic and genetic associations between reading comprehension and ADHD dimensions of inattention and…

The goal of this study was to examine how different types of social experiences in kindergarten relate to Grade 1 academic achievement, while controlling for possible genetic and shared environmental influences through the use of the monozygotic (MZ) twin difference method. Social experiences in kindergarten included relationship quality with the…

Background: Genetic risk for depressive behavior may increase the likelihood of exposure to environmental stressors (gene-environment correlation, rGE). By the same token, exposure to environmental stressors may moderate the effect of genes on depressive behavior (gene-environment interaction, GxE). Relating these processes to a peer-related…

The present study examined to what extent different types of friendship experiences (i.e., friendlessness, having depressed friends, and having nondepressed friends) are associated with early adolescents' longitudinal trajectories of depressed mood. On the basis of a sample of 201 youths (108 girls, 93 boys), we identified 3 distinct longitudinal…

Objective: This study aimed to identify the pathways through which a preventive intervention targeting young low-SES disruptive boys could result in lower crime involvement during adulthood. Method: The preventive intervention was implemented when the children were between 7 and 9 years and included three components (i.e. social skills, parental…

This study tested a transactional model of reciprocal influences regarding students' peer experiences (peer acceptance, peer rejection, and friends' academic achievement) and students' academic achievement from middle childhood to early adolescence. This longitudinal model was tested on 452 students (198 girls), mostly Caucasian and French…

This study used the monozygotic (MZ) twin difference method to examine whether the unique environmental effects of maternal and paternal overprotection and hostility at the age of 30 months predict twins' observed social reticence in a competitive situation in kindergarten, while controlling for the effect of family-wide influences, including…

This study assessed the genetic and environmental contributions to peer difficulties in the early school years. Twins' peer difficulties were assessed longitudinally in kindergarten (796 twins, "M"[subscript age] = 6.1 years), Grade 1 (948 twins, "M"[subscript age] = 7.1 years), and Grade 4 (868 twins, "M"[subscript…