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This study examined the moderating role of descriptive and status norms in the stability of youth’s antisocial behavior, and the link between initial antisocial behavior and the development of depressive symptoms over the course of one academic year, while controlling for initial depression levels. A total of 1081 students (51.06% girls; grades 4 through 6) in schools in low to average socio-economic status neighborhoods completed self-reports and a peer nomination inventory in the fall (T1) and spring (T2) of one year. Descriptive norms were operationalized as the classroom- and sex-specific mean level of antisocial behavior. Status norms were operationalized as the classroom- and sex-specific correlation between antisocial behavior and social preference. Descriptive norms moderated the link between T1 and T2 antisocial behavior, such that youth exhibiting high levels of antisocial behavior showed a greater increase in antisocial behavior in classrooms where descriptive norms strongly favored such behavior (i.e., + 1 SD) than in classrooms with neutral or weak descriptive norms (i.e., − 1 SD). Status norms moderated the association between T1 antisocial behavior and T2 depressive symptoms, such that youth with high levels of antisocial behavior had higher depressive symptoms in classrooms where status norms disfavored antisocial behavior than in classrooms with neutral or favorable norms. No moderating effects of sex or grade were observed. These results suggest that both descriptive norms and status norms play important, albeit distinct, roles in exacerbating youth’s depressive symptoms and antisocial behavior, but they may also mitigate these same outcomes in favorable contexts.

Abstract: The objectives of this study were to establish the different developmental trajectories of hyperactive–impulsive behaviors on the basis of both mother and father ratings at 19, 32, 50, and 63 months, and to examine the predictive validity of these trajectories with respect to later hyperactive–impulsive behaviors, as rated by teachers in the first 2 years of school. Hyperactive–impulsive behaviors were assessed in a population-based sample of 1,112 twins (565 boys and 547 girls) at 19, 32, 50, and 63 months of age. The results revealed a differentiated and consistent view of developmental trajectories of hyperactive–impulsive behaviors derived from these repeated assessments, with 7.1% of children seen by mothers (7% for fathers) as displaying high and stable hyperactive–impulsive behaviors. According to mother ratings, children on a high-chronic trajectory were more likely than other children to display hyperactive–impulsive behaviors at 72 and 84 months according to their teachers. Repeated measures over time and father-based trajectories significantly added to the prediction teacher later ratings of hyperactive–impulsive behaviors. These results support the predictive validity of parental assessment of hyperactive–impulsive behaviors during the preschool years and their use to identify children at risk for further evaluation and possible intervention.

Children exposed to family violence, such as child-directed and child-witnessed parental violence, tend to manifest higher levels of antisocial behaviors later in life. Genetically informed studies additionally show that antisocial behaviors are partly inherited. While there is a consensus about the polygenic nature of antisocial behavior, it remains unclear as to whether the differences present at the DNA level moderate the impact of parental violence on antisocial behaviors. This study tested whether children who were the victims of, or who witnessed, family violence exhibit more antisocial behaviors once they reach adolescence and early adulthood, and whether this risk varied according to a serotonergic polygenic index. Participants were 410 male members of the Quebec Longitudinal Study of Kindergarten Children. Child-directed and child-witnessed parental violence and participants’ antisocial behaviors were self-reported or assessed through semi-structured interviews. Previously derived haplotype-based polygenic indexes mapping to 11 serotonergic genes were used. Participants who were the victims of, or witnessed parental violence, were generally at higher risk of manifesting antisocial behaviors. Findings also offered a partial support to prior evidence for gene-environment interactions in some, but not all antisocial outcomes. Participants who were victims of child-directed parental violence and carried lower serotonergic risk were at higher risk of manifesting property or violent crimes in adulthood, supporting the Social-push model. Alternatively, participants who witnessed intra-parental violence were at higher risk of exhibiting symptoms of conduct disorder and antisocial personality disorder if they carried a higher number of haplotypic risk alleles, lending support to the Diathesis-stress model. This study extends prior work by emphasizing the need to separately investigate distinct forms of family violence and to use indicators of risk capturing variants present across multiple genes to better understand their independent and joint contributions to antisocial behaviors over the life course.

BACKGROUND: Exposure to peer victimization is relatively common. However, little is known about its developmental course and its effect on impairment associated with mental illnesses. We aimed to identify groups of children following differential trajectories of peer victimization from ages 6 to 13 years and to examine predictive associations of these trajectories with mental health in adolescence. METHODS: Participants were members of the Quebec Longitudinal Study of Child Development, a prospective cohort of 2120 children born in 1997/98 who were followed until age 15 years. We included 1363 participants with self-reported victimization from ages 6 to 13 years and data available on their mental health status at 15 years. RESULTS: We identified 3 trajectories of peer victimization. The 2 prevailing groups were participants with little or moderate exposure to victimization (441/1685 [26.2%] and 1000/1685 [59.3%], respectively); the third group (244 [14.5%]) had been chronically exposed to the most severe and long-lasting levels of victimization. The most severely victimized individuals had greater odds of reporting debilitating depressive or dysthymic symptoms (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.27-5.17), debilitating generalized anxiety problems (OR 3.27, CI 1.646.51) and suicidality (OR 3.46, CI 1.53-7.81) at 15 years than those exposed to the lowest levels of victimization, after adjustment for sex, childhood mental health, family hardship and victimization perpetration. The association with suicidality remained significant after controlling for concurrent symptoms of depression or dysthymia and generalized anxiety problems. INTERPRETATION: Adolescents who were most severely victimized by peers had an increased risk of experiencing severe symptoms consistent with mental health problems. Given that peer victimization trajectories are established early on, interventions to reduce the risk of being victimized should start before enrolment in the formal school system., Peer victimization is harm caused by peers acting outside the norms of appropriate conduct. (1) It includes (but is not limited to) bullying, which is characterized by an imbalance of [...]

Despite the substantial heritability of antisocial behavior (ASB), specific genetic variants robustly associated with the trait have not been identified. The present study by the Broad Antisocial Behavior Consortium (BroadABC) meta-analyzed data from 28 discovery samples (N= 85,359) and five independent replication samples (N= 8058) with genotypic data and broad measures of ASB. We identified the first significant genetic associations with broad ASB, involving common intronic variants in the forkhead box protein P2 (FOXP2) gene (lead SNP rs12536335, p= 6.32 × 10−10). Furthermore, we observed intronic variation in Foxp2 and one of its targets (Cntnap2) distinguishing a mouse model of pathological aggression (BALB/cJ strain) from controls (BALB/cByJ strain). Polygenic risk score (PRS) analyses in independent samples revealed that the genetic risk for ASB was associated with several antisocial outcomes across the lifespan, including diagnosis of conduct disorder, official criminal convictions, and trajectories of antisocial development. We found substantial genetic correlations of ASB with mental health (depression rg= 0.63, insomnia rg= 0.47), physical health (overweight rg= 0.19, waist-to-hip ratio rg= 0.32), smoking (rg= 0.54), cognitive ability (intelligence rg= −0.40), educational attainment (years of schooling rg= −0.46) and reproductive traits (age at first birth rg= −0.58, father’s age at death rg= −0.54). Our findings provide a starting point toward identifying critical biosocial risk mechanisms for the development of ASB.

Commonly comorbid early onset psychiatric disorders might reflect the varying expression of overlapping risk factors. The mediating processes remain poorly understood, but three factors show some promise: adolescent externalizing traits, early life adversity, and midbrain dopamine autoreceptors. To investigate whether these features acquire greater predictive power when combined, a longitudinal study was conducted in youth who have been followed since birth. Cohort members were invited to participate based on externalizing scores between 11 to 16 years of age. At age 18 (age 18.5 ± 0.6 y.o.), 52 entry criteria meeting volunteers had a 90-min positron emission tomography scan with [18F]fallypride, completed the Childhood Trauma Questionnaire, and were assessed with the Structured Clinical Interview for DSM-5. The three-factor model identified those with a lifetime history of DSM-5 disorders with an overall accuracy of 90.4% (p= 2.4 × 10−5) and explained 91.5% of the area under the receiver operating characteristic curve [95% CI: .824, 1.000]. Targeting externalizing disorders specifically did not yield a more powerful model than targeting all disorders (p= 0.54). The model remained significant when including data from participants who developed their first disorders during a three-year follow-up period (p= 3.5 × 10−5). Together, these results raise the possibility that a combination of temperamental traits, childhood adversity, and poorly regulated dopamine transmission increases risk for diverse, commonly comorbid, early onset psychiatric problems, predicting this susceptibility prospectively.

Objective: Only a minority of drug and alcohol users develops a substance use disorder. Previous studies suggest that this differential vulnerability commonly reflects a developmental trajectory characterized by diverse externalizing behaviors. In this study, we examined the relation between child and adolescent externalizing behaviors and adolescent substance use in a prospectively followed Canadian birth cohort, accounting for the temporal sequence of a wide variety of contributing factors.Methods: Two hundred and forty-two adolescents followed since birth (date range: 1996 to 2012) were assessed on externalizing behavior (age 17 months to 16 years), alcohol and cannabis use at age 16, age of alcohol use onset, family history of substance use problems, family functioning (age 11 to 15), sensation seeking (age 16), prenatal substance exposure, socioeconomic status (age 1 to 9), and sex.Results: Age of alcohol use onset was predicted by a family history of substance use problems, externalizing traits from ages 6 to 10 and 11 to 16, sensation seeking at age 16, prenatal alcohol and tobacco exposure and family functioning at ages 11 to 15. High frequencies of alcohol and cannabis use at age 16 were both predicted by externalizing traits from ages 11 to 16, a family history of substance use problems and sensation seeking after controlling for other individual, environmental and familial variables. The association between familial substance use problems and substance use during adolescence was partially mediated by externalizing traits from age 11 to 16.Conclusions: The present findings provide prospective evidence for a developmental risk pathway for adolescent substance use, potentially identifying those who could benefit from early interventions.

The excitatory neurotransmitter glutamate has been implicated in experience-dependent neuroplasticity and drug-seeking behaviors. Type 5 metabotropic glutamate (mGlu5) receptors might be particularly important. They are critically involved in synaptic plasticity and their availability has been reported to be lower in people with alcohol, tobacco, and cocaine use disorders. Since these reductions could reflect effects of drug use or pre-existing traits, we used positron emission tomography to measure mGlu5 receptor availability in young adults at elevated risk for addictions. Fifty-nine participants (age 18.5 ± 0.6) were recruited from a longitudinal study that has followed them since birth. Based on externalizing traits that predict future substance use problems, half were at low risk, half were at high risk. Cannabis use histories varied markedly and participants were divided into three subgroups: zero, low, and high use. Compared to low risk volunteers, those at elevated risk had lower [11C]ABP688 binding potential (BPND) values in the striatum, amygdala, insula, and orbitofrontal cortex (OFC). Cannabis use by risk group interactions were observed in the striatum and OFC. In these regions, low [11C]ABP688 BPNDvalues were only seen in the high risk group that used high quantities of cannabis. When these high risk, high cannabis use individuals were compared to all other participants, [11C]ABP688 BPNDvalues were lower in the striatum, OFC, and insula. Together, these results provide evidence that mGlu5 receptor availability is low in youth at elevated risk for addictions, particularly those who frequently use cannabis.

The neurobiological traits that confer risk for addictions remain poorly understood. However, dopaminergic function throughout the prefrontal cortex, limbic system, and upper brainstem has been implicated in behavioral features that influence addiction vulnerability, including poor impulse control, and altered sensitivity to rewards and punishments (i.e., externalizing features). To test these associations in humans, we measured type-2/3 dopamine receptor (DA2/3R) availability in youth at high vs. low risk for substance use disorders (SUDs). In this study, N= 58 youth (18.5 ± 0.6 years) were recruited from cohorts that have been followed since birth. Participants with either high (high EXT; N= 27; 16 F/11 M) or low pre-existing externalizing traits (low EXT; N= 31; 20 F/11 M) underwent a 90-min positron emission tomography [18F]fallypride scan, and completed the Barratt Impulsiveness Scale (BIS-11), Substance Use Risk Profile scale (SURPS), and Sensitivity to Punishment (SP) and Sensitivity to Reward (SR) questionnaire. We found that high vs. low EXT trait participants reported elevated substance use, BIS-11, SR, and SURPS impulsivity scores, had a greater prevalence of psychiatric disorders, and exhibited higher [18F]fallypride binding potential (BPND) values in prefrontal, limbic and paralimbic regions, even when controlling for substance use. Group differences were not evident in midbrain dopamine cell body regions, but, across all participants, low midbrain BPNDvalues were associated with low SP scores. Together, the results suggest that altered DA2/3R availability in terminal extra-striatal and dopamine cell body regions might constitute biological vulnerability traits, generating an EXT trajectory for addictions with and without co-occurring alterations in punishment sensitivity (i.e., an internalizing feature).

Objective: Traumatic brain injuries (TBIs) are sustained by approximately 17% of males in the general population, many of whom subsequently present mental disorders, cognitive, and physical problems. Little is known about predictors of TBIs and how to prevent them. The present study aimed to determine whether inattention–hyperactivity and/or all externalizing problems presented by boys at age 10 predict subsequent TBIs to age 34 after taking account of previous TBIs and family social status (FSS).Method: 742 Canadian males were followed, prospectively, from age 6 to 34. Diagnoses of TBIs were extracted from health files, parents-reported sociodemographic and family characteristics at participants’ age 6, and teachers-rated participants’ behaviors at age 10. Separate logistic regression models predicted TBIs sustained from age 11 to 17 and from age 18 to 34. For each age period, two models were computed, one included previous TBIs, inattention–hyperactivity, FSS, and interaction terms, the second included previous TBIs, externalizing problems, FSS, and interaction terms.Results: In models that included inattention–hyperactivity, TBIs sustained from age 11 to 17 were predicted by age 10 inattention–hyperactivity (odds ratio [OR] = 1.46, 1.05 to 2.05) and by TBIs prior to age 11 (OR= 3.50, 1.48 to 8.24); TBIs sustained from age 18 to 34 were predicted by age 10 inattention–hyperactivity (OR= 1.31, 1.01 to 170). In models that included all externalizing problems, TBIs from age 11 to 17 were predicted by prior TBIs (OR= 3.66, 1.51 to 8.39); TBIs sustained from age 18 to 34 were predicted by age 10 externalizing problems (OR= 1.45, 1.12 to 1.86). Neither FSS nor interaction terms predicted TBIs in any of the models.Conclusions: Among males, using evidence-based treatments to reduce inattention–hyperactivity and externalizing problems among boys could, potentially, decrease the risk of TBIs to age 34. Further, boys who sustain TBIs in childhood require monitoring to prevent recurrence in adolescence.

Eating-disorder symptoms, such as body image issues, maladaptive behaviors, and preoccupation with weight, tend to develop in adolescence. However, it is unclear whether early childhood characteristics or behaviours could be indicators of a risk of developing eating-disorder symptoms later. The current study examined the possible link between certain early behaviours (e.g., hyperactivity, childhood eating), early cognitive processes, and eating-disorder symptoms development in a community cohort followed from birth. Results showed that being hyperactive in early childhood predicts higher levels of eating-disorder symptoms at the beginning of adolescence (age 15), and that this is partially explained by a link between being hyperactive, being more rigid in our ways of thinking, and engaging in overeating behaviours. Additionally, more early rigid ways of thinking predicted the increase in symptoms over time. Our results demonstrate possible behaviours and characteristics that could be used to identify children at risk of eating disorders, which in future research could potentially help improve our preventive interventions.

IMPORTANCE: Identifying early childhood behavioral problems associated with economic success/failure is essential for the development of targeted interventions that enhance economic prosperity through improved educational attainment and social integration. OBJECTIVE: To test the association between kindergarten teacher–rated assessments of inattention, hyperactivity, opposition, aggression, and prosociality in boys with their employment earnings at age 35 to 36 years as measured by government tax return data. DESIGN, SETTING, AND PARTICIPANTS: A 30-year prospective follow-up study analyzing low socioeconomic neighborhoods in Montreal, Quebec, Canada. Boys aged 5 to 6 years attending kindergarten in low socioeconomic neighborhoods were recruited. Teacher-rated behavioral assessments were obtained for 1040 boys. Data were collected from April 1984 to December 2015. Analysis began January 2017. MAIN OUTCOMES AND MEASURES: Mixed-effects linear regression models were used to examine the association between teacher ratings of inattention, hyperactivity, opposition, aggression, and prosociality at age 6 years and individual earnings obtained from government tax returns at age 35 to 36 years. The IQ of the child and family adversity were adjusted for in the analysis. RESULTS: Complete data were available for 920 study participants (mean age at follow-up was 36.3 years). Mean (SD) personal earnings at follow-up were $28 865.53 ($24 103.45) (range, $0-$142 267.84). A 1-unit increase in inattention (mean [SD], 2.66 [2.34]; range, 0-8) at age 6 years was associated with decrease in earnings at age 35 to 36 years of $1295.13 (95% CI, −$2051.65 to −$538.62), while a unit increase in prosociality (mean [SD], 8.0 [4.96]; range, 0-20) was associated with an increase in earnings of $406.15 (95% CI, $172.54-$639.77). Hyperactivity, opposition, and aggression were not significantly associated with earnings. Child IQ was associated with higher earnings and family adversity with lower earnings in all models. A 1-SD reduction in inattention at age 6 years was associated with a theoretical increase in annual earnings of $3040.41, a similar magnitude to an equivalent increase in IQ. CONCLUSIONS AND RELEVANCE: Teacher ratings of inattention and prosociality in kindergarten boys from low socioeconomic neighborhoods are associated with earnings in adulthood after adjustment for hyperactivity, aggression, and opposition, which were not associated with earnings. Interventions beginning in kindergarten that target boys’ inattention and enhance prosociality could positively impact workforce integration and earnings.

Epigenetic processes that regulate gene expression, such as DNA methylation (DNAm), have been linked to individual differences in physical aggression. Yet, it is currently unclear whether: (a) DNAm patterns in humans associate with physical aggression independently of other co‐occurring psychiatric and behavioral symptoms; (b) whether these patterns are observable across multiple tissues; and (c) whether they may function as a causal versus noncausal biomarker of physical aggression. Here, we used a multisample, cross‐tissue design to address these questions. First, we examined genome‐wide DNAm patterns (buccal swabs; Illumina 450k) associated with engagement in physical fights in a sample of high‐risk youth (n= 119; age = 16–24 years; 53% female). We identified one differentially methylated region in DRD4,which survived genome‐wide correction, associated with physical aggression above and beyond co‐occurring symptomatology (e.g., ADHD, substance use), and showed strong cross‐tissue concordance with both blood and brain. Second, we found that DNAm sites within this region were also differentially methylated in an independent sample of young adults, between individuals with a history of chronic‐high versus low physical aggression (peripheral T cells; ages 26–28). Finally, we ran a Mendelian randomization analysis using GWAS data from the EAGLE consortium to test for a causal association of DRD4methylation with physical aggression. Only one genetic instrument was eligible for the analysis, and results provided no evidence for a causal association. Overall, our findings lend support for peripheral DRD4methylation as a potential biomarker of physically aggressive behavior, with no evidence yet of a causal relationship.

The present study examined 1) whether the associations between cannabis use (CU) age of onset and drug abuse by 28 y remain when controlling for risk factors in childhood, adolescence and early adulthood; and 2) the developmental pathways from early risk factors to drug abuse problems. Participants from a longitudinal sample of boys of low socioeconomic status (N= 1,030) were followed from 6 to 28 y. We examined the self-reported CU onset between the ages of 13 and 17 y and drug abuse symptoms by 28 y. The odds of developing any drug abuse symptoms by 28 y were reduced by 31% for each year of delayed CU onset (OR = 0.69). Cannabis, alcohol and other drug frequency at 17 y mediated this association. Still, even when taking that frequency of use into account, adolescents who started using cannabis before 15 y were at a higher risk of developing drug abuse symptoms by age 28 y. Significant indirect effects were found from early adolescent delinquency and affiliation with deviant friends to drug abuse symptoms at 28 y through CU age of onset and substance use frequency at 17 y. The results suggest more clearly than before that prevention programs should aim at delaying CU onset to prevent or reduce drug abuse in adulthood. Furthermore, prevention programs targeting delinquency and/or affiliation with deviant friends in childhood or early adolescence could indirectly reduce substance abuse in adulthood without addressing substance use specifically.

Objective: This study investigated the possible relationship between impulsivity in early adolescence and gambler status in late adolescence. Method: Impulsivity measures consisting of self-reports and teacher ratings were gathered from 754 boys in early adolescence, and their gambling status in late adolescence was assessed with a self-report measure. Results: On both measures of impulsivity, nongamblers had the lowest scores, recreational gamblers had the next higher scores, low problem gamblers had still higher scores, and high problem gamblers had the highest scores. Conclusions: These findings support the DSM-IV classification of problem gambling as a deficit in impulse control.

Eating disorders, typically involving preoccupation with eating, excessive exercise, and body image issues, are particularly common in adolescence. However, their evolution over time remains unclear as certain signs and symptoms may appear sooner than others. The current study studied the development of eating disorder symptoms in a community cohort followed from birth to adulthood. This study describes trajectories of eating disorder symptoms and risk from age 12 to 20 in both boys and girls. Results showed that the largest increase in eating disorder symptoms occurs between 12 and 15 years of age, both in overall symptomatology as well as in specific symptoms such as loss-of-control when eating, feeling overweight, and attributing importance to food. Additionally, more girls than boys appeared at risk for eating disorders, although the patterns represented by the trajectories were similar in both sexes. Our results highlight the importance of starting early prevention programs before the beginning of adolescence, when symptoms usually start to manifest.

Using a 17-year longitudinal design, this study examined the role of personal and family factors assessed early in life, and also academic and social experiences assessed in the first year of college, in predicting college completion. We followed a sample of 444 French-speaking Canadian children from middle to upper socioeconomic backgrounds (66% boys and 34% girls; 6 years old at study onset). We assessed social behaviors (i.e., aggressive-disruptive, anxiety-withdrawal, and prosocial behaviors), mothers’ child-rearing practices (i.e., discipline and pleasure), and family resources (i.e., family structure, mothers’ education, and mothers’ age at the birth of the first child) at kindergarten; academic records in elementary and high school; and academic and social integration in college (i.e., adjustment to academic requirements, academic success, participation in social activities, and attachment to the institution). College completion at age 23 years was obtained from national official records. Using logistic regression analysis, we found that previous social behaviors, academic records, and family experiences had greater impact on college completion than did the quality of students’ academic and social integration in college. We propose some avenues to better understand how precollege factors can improve a child's academic trajectory, college aspirations, and chances of success.

IMPORTANCE: Childhood sleepwalking and sleep terrors are 2 parasomnias with a risk of serious injury for which familial aggregation has been shown. OBJECTIVES: To assess the prevalence of sleepwalking and sleep terrors during childhood; to investigate the link between early sleep terrors and sleepwalking later in childhood; and to evaluate the degree of association between parental history of sleepwalking and presence of somnambulism and sleep terrors in children. DESIGN, SETTING, AND PARTICIPANTS: Sleep data from a large prospective longitudinal cohort (the Quebec Longitudinal Study of Child Development) of 1940 children born in 1997 and 1998 in the province were studied from March 1999 to March 2011. MAIN OUTCOMES AND MEASURES: Prevalence of sleep terrors and sleepwalking was assessed yearly from ages 11/2 and 21/2 years, respectively, to age 13 years through a questionnaire completed by the mother. Parental history of sleepwalking was also queried. RESULTS: The peak of prevalence was observed at 11/2 years for sleep terrors (34.4% of children; 95% CI, 32.3%-36.5%) and at age 10 years for sleepwalking (13.4%; 95% CI, 11.3%-15.5%). As many as one-third of the children who had early childhood sleep terrors developed sleepwalking later in childhood. The prevalence of childhood sleepwalking increases with the degree of parental history of sleepwalking: 22.5% (95% CI, 19.2%-25.8%) for children without a parental history of sleepwalking, 47.4% (95% CI, 38.9%-55.9%) for children who had 1 parent with a history of sleepwalking, and 61.5% (95% CI, 42.8%-80.2%) for children whose mother and father had a history of sleepwalking. Moreover, parental history of sleepwalking predicted the incidence of sleep terrors in children as well as the persistent nature of sleep terrors. CONCLUSIONS AND RELEVANCE: These findings substantiate the strong familial aggregation for the 2 parasomnias and lend support to the notion that sleepwalking and sleep terrors represent 2 manifestations of the same underlying pathophysiological entity.

DNA methylation patterns are characterized by highly conserved developmental programs, but allow for divergent gene expression resulting from stochastic epigenetic drift or divergent environments. Genome-wide methylation studies in monozygotic (MZ) twins are providing insight into the extent of epigenetic variation that occurs, irrespective of genotype. However, little is known about the variability of DNA methylation patterns in adolescence, a period involving significant and rapid physical, emotional, social, and neurodevelopmental change. Here, we assessed genome-wide DNA methylation using the 450 K Illumina BeadChip in a sample of 37 MZ twin pairs followed longitudinally since birth to investigate: 1) the extent of variation in DNA methylation in identical genetic backgrounds in adolescence and; 2) whether these variations are randomly distributed or enriched in particular functional pathways. We also assessed stability of DNA methylation over 3–6 months to distinguish stable trait-like and variable state-like genes. A pathway analysis found high within-pair variability in genes associated with development, cellular mechanisms, tissue and cell morphology, and various disorders. Test-retest analyses performed in a sub-sample of 8 twin pairs demonstrated enrichment in gene pathways involved in organismal development, cellular growth and proliferation, cell signaling, and particular disorders. The variability found in functional gene pathways may plausibly underlie phenotypic differences in this adolescent MZ twin sample. Furthermore, we assessed stability of methylation over 3–6 months and found that some genes were stable while others were unstable, suggesting that the methylome remains dynamic in adolescence and that dynamic sites tend to be organized in certain gene pathways.

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.

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.

The aims of this research were twofold: to investigate the relationship between family adversity (based on a composite index) and the number of teacher-rated behaviourally disordered children in kindergarten and to examine the relationship between family adversity and the stability of behavioural disorders from kindergarten to grade one. The sample was comprised of 3,026 children who were rated by their kindergarten and grade one teachers on three behavioural dimensions (aggressiveness-disruptiveness—13 items; anxiety-withdrawal—6 items; prosociality—10 items) using the Preschool Behavior Questionnaire (Behar & Stringfield, 1974) and the Pro-social Behavior Questionnaire (Weir & Duveen, 1981). The Family Adversity Index (FAI) was based on information provided by mothers pertaining to family structure, parents' occupation, parents' education level, and parents' age at the birth of the child. According to teacher ratings, children who obtained a score of 1.5 standard deviations above the mean of their same-gender classmates on the aggressiveness-disruptiveness and anxiety-withdrawal scales or 1.5 standard deviations below the mean of their same-gender classmates on the prosociality scale were classified as extremes on each of these dimensions. These were termed the “extreme cases.” Results showed that the number of extreme cases on the aggressiveness-disruptiveness scale in kindergarten was significantly related to FAI for both genders. Moreover, the number of extreme aggressive-disruptive cases who remained extreme after making the transition to grade one (i.e., stable cases) was also significantly related to FAI. For both genders, twice more stable aggressive-disruptive cases had a high FAI (i.e., top third) compared to transient extreme cases (i.e., extreme in kindergarten only). Discussion underlines the link between family adversity and incidence and persistence of behavioural problems during the early school years. It also stresses the need to consider family adversity to screen stable extreme aggressive-disruptive cases in kindergarten for early intervention purposes.

Dans une perspective de prévention, it s'avére de plus en plus important et urgent pour les intervenants communautaires en santé mentale, d'identifier correctement les groupes les plus vulnérables. Une étude d'archives effectuée dans une clinique externe de la région de l'Abitibi-Temiscamingue permet d'identifier certaines populations à risque en santé mentale et certains facteurs environnementaux pouvant contribuer à perturber l'équilibre biopsychosocial des individus. Des comparaisons effectuées en d'autres régions ou d'autres pays indiquent que ces analyses sont en grande partie généralisables.

Attention deficit hyperactivity disorder ADHD is the most prevalent psychiatric disorder emerging during childhood. Psychostimulant medications e.g., methylphenidate noticeably reduce ADHD symptoms in most children. Since methylphenidate inhibits dopamine transporter activity, the dopamine transporter gene DAT1 was considered to be the prime candidate risk gene in ADHD. Several studies found evidence for an association between the 10repeat allele of the variable number of tandem repeat VNTR located in the 3′ untranslated region and ADHD andor ADHD symptoms in clinical and populationbased samples. However, this finding was not replicated in all samples. In this study, we investigated the association between the DAT1gene and ADHD symptoms in a populationbased twin sample from Québec Canada. We used two polymorphisms, the VNTR and rs27072, the last providing the most significant results in a clinical sample from Toronto Ontario, Canada. No association was noted between the VNTR and ADHD symptoms in children at 6 and 7 years of age, as reported by teachers. However, a significant association was found for the rs27072 polymorphism and symptoms of inattention and hyperactivityimpulsivity. These findings indicate that the DAT1gene contributes to ADHD symptoms in this sample and further suggest that the VNTR may not be the optimal polymorphism for study in all populations. © 2007 WileyLiss, Inc.

Longitudinal Methods Based on Individual Development Trajectories - Parametricand Non Parametric Mixed Models: Generalized linear mixed models encompass a variety of modern longitudinal analytic approaches based on individual developmental trajectories. These models overcome many important problems inherent to other traditional analysis of longitudinal data. They all rely on two basic levels: the lower one express, through a set of parameters, the individual pattem of change over time (within-individualchange), whereas the upper level captures the variations between these parameters describing individual trajectories (between-individualdifferences in change). However, other characteristics distinguish différent sorts of mixed models, such as their assumptions concerning the distribution of the trajectories within the population. This introductory article presents the basic linear mixed model assuming a normal distribution of the unobserved heterogeneity, and the nonparametric mixture model that relies on a discrete approximation of the unobserved heterogeneity. Before comparing these two models, the first section of the article gives a general description of the notion of individual developmental trajectories.

Background: This study examined the elevated heart rate (HR) response to alcohol intoxication, thought to reflect an increased sensitivity to alcohol‐induced reward, as a potential factor in the increased likelihood of alcohol‐induced aggression.

Objective: To investigate sex and informant effects on comorbidity rates for anxiety disorders, depressive disorders, attention-deficit hyperactivity disorder (ADHD), and conduct–oppositional disorder (CD–ODD) in an adolescent community sample.Method: The Diagnostic Interview Schedule for Children-2.25 (DISC-2.25) was administered to 1201 adolescents and their mothers.Results: The highest comorbidity risk found was between ADHD and CD–ODD, with odds ratios (ORs) of 17.6 for adolescent reports and 12.0 for mother reports. The second-highest comorbidity risk, with ORs of 13.2 for adolescent reports and 11.0 for mother reports, was between anxiety and depressive disorders. There was not much overlap between internalizing and externalizing disorders. Adolescent girls had higher rates of coexisting anxiety and depressive disorders, whereas adolescent boys had higher rates of coexisting ADHD and CD–ODD. There was partial support for the hypothesis that adolescent-reported comorbidity rates would exceed mother-reported rates.Conclusions: There is a greater cooccurrence of within-category, compared with between-category, disorders. Adolescent girls are more likely to have coexisting internalizing disorders, while adolescent boys are more likely to have coexisting externalizing disorders. Mothers tend to report more externalizing disorders (that is, ADHD), while adolescents generally report more internalizing disorders.

Labelling cigarettes as “light” or “mild” is claimed to be one of the biggest marketing scams in Canadian history. Arguably, such labelling implies that these varieties of cigarettes are less harmful than “regular” cigarettes. In Canada, a food product can be labelled “light” if there is a 25% reduction from the “reference food” and if the constituent being reduced is clearly identified (e.g., light in fat). Cigarette labelling does not comply with these regulations, however. To examine whether or not some tobacco constituents meet the 25% reduction criterion, we compared yields of 41 toxic and/or carcinogenic smoke constituents in six varieties of “light” cigarettes to the yields of “regular” cigarettes. We selected cigarettes from the two most popular Canadian brands, Du Maurier and Players. Using a set of data provided by Imperial Tobacco Canada and made available to the public by the Government of British Columbia, we compared yields measured under a laboratory protocol (modified ISO) that was designed to provide a more rigorous evaluation of the differences between varieties of cigarettes and a more accurate assessment of smokers’ potential smoke intake than the traditional protocol (standard ISO). For all six varieties of “light” cigarettes, the yields of nicotine were higher by an average of 5% (range: 1% to 13%). The 25% reduction criterion was not met for any variety of “light” cigarettes concerning yields of tar. For all cigarettes tested, yields of tar were reduced on average by only 16% (range: 5% to 22%). For carbon monoxide (CO), only Player’s Smooth Light had an over 25% reduction (30%) compared with Player’s Regular. Conversely, yield of CO was 24% higher for Du Maurier Lights compared with Du Maurier Regular. As for the other smoke constituents, the majority (75%) were not reduced by 25% or more in “light” cigarettes, and a sizeable proportion of yields (e.g., acrylonitrile, benzene, chromium, m+p cresol, mercury, nickel, toluene) were larger in these varieties of cigarettes. Only yields of formaldehyde, crotonaldehyde, 1-aminonaphtalene, and proprionaldehyde were systematically reduced in all varieties of “light” cigarettes. The six varieties of “light” cigarettes examined in this study do not differ substantially from “regular” cigarettes in terms of smoke yields. We argue that the modified ISO protocol should be implemented for a more valid comparison of potential smoke yields in all varieties of cigarettes and that labelling based on this protocol should be promoted. L’utilisation de descriptifs comme « légères » ou « douces » sur les emballages de cigarettes serait l’une des plus grandes fumisteries de l’histoire du marketing au Canada. En effet, cet étiquetage donne à penser que ces variétés de cigarettes sont moins nocives pour la santé que les cigarettes « ordinaires ». Au Canada, un aliment peut être étiqueté comme étant « allégé » si on mentionne ce qui est réduit (p. ex., « allégé en matières grasses ») et si le produit est allégé d’au moins 25 % par rapport à l’aliment de référence. Ces règles ne sont cependant pas employées pour l’étiquetage des cigarettes. Afin de déterminer si certaines substances présentes dans la fumée de tabac sont réduites d’au moins 25 % dans les cigarettes « légères », nous avons comparé les niveaux d’émission de 41 constituants toxiques et/ou carcinogènes de six variétés de cigarettes « légères » avec les niveaux d’émission des cigarettes « ordinaires ». Pour ces comparaisons, nous avons choisi les deux marques canadiennes les plus populaires: Du Maurier et Player’s. Nous avons utilisé les données fournies par Imperial Tobacco Canada rendues publiques par le gouvernement de la Colombie-Britannique. Nous avons examiné les émissions des différents constituants, obtenues au moyen d’un protocole de laboratoire (norme ISO modifiée) qui, comparativement à la méthode classique (norme ISO standard), permet une évaluation plus juste de la quantité de fumée potentiellement inhalée par le fumeur. Les niveaux d’émission de nicotine sont plus élevés de 5 % en moyenne (entre 1 % et 13 %) dans les cigarettes « légères » que dans les cigarettes « ordinaires ». En ce qui concerne les niveaux d’émission de goudron, la réduction moyenne pour les différentes variétés de cigarettes « légères » est de 16 % seulement (entre 5 % et 22 %), et n’atteint en aucun cas le seuil de 25 %. Pour ce qui est des niveaux d’émission de monoxyde de carbone (CO), les cigarettes Player’s Légères Veloutées affichent une baisse de plus de 25 % (30 %), mais les cigarettes Du Maurier Légères ont quant à elles un taux d’émission de CO de 24 % supérieur à celui des Du Maurier Régulières. Quant aux autres constituants toxiques de la fumée de tabac, la plupart (75 %) des niveaux d’émission relevés pour les cigarettes « légères » n’atteignent pas le seuil de réduction de 25 %. De plus, les niveaux d’émission de plusieurs constituants (acrylonitrile, benzène, chromium, m+p crésol, mercure, nickel, toluène) sont substantiellement plus élevés dans les cigarettes « légères ». Seules les émissions de formaldéhyde, de crotonaldéhyde, de 1-aminonaphtalène et de proprionaldéhyde sont systématiquement réduites dans ces variétés de cigarettes. Les cigarettes « légères » examinées dans la présente étude diffèrent peu des cigarettes « ordinaires ». À notre avis, il faudrait mettre en œuvre le protocole ISO modifié afin de fournir une comparaison plus juste des émissions toxiques des différentes variétés de cigarettes. Enfin, nous pensons que l’étiquetage devrait refléter les résultats comparatifs obtenus au moyen de ce protocole.

Our objective is to advance the life course analytical framework by demonstrating a model for testing two of its tenets. The first is whether the individual's developmental history conditions the response to a turning point event. The second is whether the influence of a major life event upon an individual's developmental course depends upon the timing of the event. We test both propositions in an analysis of the effect of grade retention on a child's trajectory of physical aggression. Our analysis is based on data from a longitudinal study of 1,037 boys from schools in the lowest socioeconomic areas in Montreal, Canada. We find clear evidence that a developmental history of physical aggression conditions the child's response to grade retention. The evidence on whether the timing of retention affects this response is less clear.

Being part of a delinquent group has been shown to facilitate the expression of an individual's own delinquent propensities. However, this facilitation effect has not been investigated from a developmental perspective within a population heterogeneity model. Using a semiparametric mixture model with data from the Montreal Longitudinal Experimental Study, this article addresses important issues in the developmental trends of membership to delinquent groups. We explore how the rate of violent behaviors follows delinquent peer group trajectories and investigate a differential facilitation effect of delinquent peers on violence across multiple developmental pathways. Results suggest that 25% of males followed a childhood or an adolescence delinquent group affiliation trajectory. These two groups account for most of the violent acts assessed during adolescence. In addition, the rate of violent behaviors follows these developmental trajectories. Controlling for these delinquent group trajectories, we also found that being involved in a delinquent group at any specific time during adolescence is associated with an increased rate of violent behaviors, and that leaving these groups results in a decrease in violent behaviors. This facilitation effect appears homogeneous over time and across developmental trajectories. Results are discussed from a social interactional perspective.

A longitudinal study with a nested preventive intervention was used to test five hypotheses generated from developmental theories of antisocial behavior. The longitudinal study followed 909 boys from their kindergarten year up to 17 years of age. The randomized multimodal preventive intervention targeted a subsample of boys who were rated disruptive by their kindergarten teacher. Semiparametric analyses of developmental trajectories for self-reported physical aggression, vandalism, and theft identified more types of trajectories than expected from recent theoretical models. Also, these trajectories did not confirm theoretical models, which suggest a general increase of antisocial behavior during adolescence. The majority of boys were on either a low-level antisocial behavior trajectory or a declining trajectory. Less than 6% appeared to follow a trajectory of chronic antisocial behavior. Comparisons between disruptive and nondisruptive kindergarten boys confirmed the hypothesis that disruptive preschool children are at higher risk of following trajectories of frequent antisocial behavior. Comparisons between treated and untreated disruptive boys confirmed that an intensive preventive intervention between 7 and 9 years of age, which included parent training and social skills training, could change the long-term developmental trajectories of physical aggression, vandalism, and theft for disruptive kindergarten boys in low socioeconomic areas. The results suggest that trajectories of violent behavior can be deflected by interventions that do not specifically target the physiological deficits that are often hypothesized to be a causal factor. The value of longitudinal–experimental studies from early childhood onward is discussed.

Research on gambling clearly demonstrates that today's youth are very much involved in gambling activities. As they take part in these activities, young people develop and entertain irrational thoughts about gambling and become at risk for developing severe gambling problems. In this study, a video specifically designed to correct misconceptions and increase knowledge about gambling was tested on 424 grade 7 and 8 students. The effectiveness of the video was evaluated using four different experimental conditions. Findings indicated that the video significantly improved subjects' knowledge about gambling and corrected their misconceptions. The implications of these results for the prevention of gambling problems are discussed.

The purpose of this study was threefold: (1) to assess the possible mutual influence between gambling, substance use, and delinquency over a two-year period during mid adolescence, (2) to test whether variables that are usually predictive of delinquency and substance use also predict gambling, and (3) to test whether the links between the three problem behaviors could be, at least partially, accounted for by common antecedent factors (impulsivity, parental supervision, and deviant friends) assessed during early adolescence. Seven hundred and seventeen boys participated in the study. Impulsivity, parental supervision, and friends' deviancy were collected when participants were 13 and 14 years of age. Gambling, substance use, and delinquency were collected through self-reports at ages 16 and 17 years. Results showed no influence or modest influence of problem behaviors on each other from age 16 to age 17 years, once current links and auto-correlations were accounted for. Conversely, the cross-sectional links between the three problem behaviors at each age were moderately high. Impulsivity, low parental supervision, and deviant friends were predictively related to each problem. Finally, a significant, although modest, portion of the covariance between the three problem behaviors was accounted for by these three predictors. The present findings contradict previous findings about the influence of gambling on other problem behaviors and support the notion of a “general problem behavior syndrome” fed by generic risk factors.

Several investigators have underlined the importance of long-term prevention programs in order to expect positive results for at-risk children. One essential prerequisite to addressing this issue is the retention of participants in such programs. The present study aims at examining the contribution of mother–child interactions, mother's social isolation, improvement in the mother–child relationship, and improvement in the child's behavior to the prediction of persistence. Participants (n= 59 disruptive boys) were recruited for a 3-year multicomponent preventive intervention program. Results indicated an improvement of the boys' behavior (reduction of inattention/hyperactivity and reduction of fighting) during the first year of the program, and showed that mother–child positive interactions before the beginning of the program were the best predictors of persistence. Implications of these results for long-term preventive programs are discussed.

This study examined the controversial practice of grade retention and children's academic and behavioral adjustment using data from the Quebec Longitudinal Study of Kindergarten Children. We employed an autoregressive modeling technique to detect the impact of being held back during primary school on subsequent academic performance and behavioral development until age 12 years. The results indicate both a short- and long-term negative influence on academic performance for boys and girls. Children's anxious, inattentive, and disruptive behaviors persisted and, in some cases, worsened after grade retention. These prospective associations were long lasting and more pronounced when grade retention occurred early in primary school. Boys were more vulnerable to the negative influence of grade retention on academic performance and classroom disruptiveness. Disruptive behavior in girls was comparatively less associated with long-term consequences than boys. Nevertheless, girls experienced both short- and long-term academic performance problems in the aftermath of grade retention. Children's prosocial behavior appeared unaffected by grade retention. These results are independent of what would have been expected by the natural course of academic and behavioral development.

This study compares the attitudes, knowledge, and behavior of parents of 5- to 17-year-old children regarding youth gambling. This information was obtained through two telephone surveys conducted in 1995, and 5 years later in 2000, in the Québec City area. Survey 1, in 1995, was conducted on 279 respondents, while survey 2, in 2000, was carried out with 213 respondents. Results showed a number of changes in parents' attitudes, behavior, and knowledge concerning youth gambling: For example, parents' perception of the age of onset of gambling behavior had improved slightly at the end of the 5-year period. Furthermore, parents were more satisfied with government limitation of access to gambling, and more accurately informed about legal aspects of the sale of lottery tickets. However, the percentage of parents who failed to associate youth gambling with some of its correlates (arcade attendance, parental gambling problems, and friendship with gamblers) increased from 1995 to year 2000. The improvements that were observed suggested that parents had benefited from media-transmitted information during this period. However, the deterioration of some parental attitudes, and the stability of other variables, suggest that it is still important to educate parents about youth gambling, and to design interventions adapted to parents' needs.

Objectifs: La présente études 'intéresse aux caractéristiques personnelles et familiales des enfants de pères alcooliques qui ne développent pas de problème d'alcool et/ou de drogue à l'adolescence (c 'est à dire, les enfants résilients) en comparaison avec ceux qui en développent. Divers traits comportementaux sont examinés comme facteurs de résilience ainsi que certaines pratiques éducatives des parents.Méthode: Les facteurs de résilience sont évalués tout au cours de l'enfance, soit entre l'âge de 6 et 12 ans. La présence ou l'absence de problème d'alcool et/ou de drogue chez le jeune est établie à l'âge de 15 ou 16 ans.Résultats: Près de 1000jeunes des 2 sexes ont participé à l'étude. Comme prévu, l'alcoolisme du père constitue un facteur de risque important en regard des problèmes de consommation des substances psychotropes à l'adolescence. Des traits de personnalité comme une faible recherche de sensations ainsi qu'une propension à l'inhibition constituent, au contraire, des facteurs qui diminuent le risque d'éprouver des problèmes de consommation. Ces facteurs ne peuvent cependant être considérés comme des facteurs de resilience car leur effet s'exerce autant chez les enfants de pères non alcooliques que chez ceux de pères alcooliques. Par contre, la supervision parentale s'est avérée protectrice car elle a diminué le risque de problème de consommation seulement chez les enfants de pères alcooliques.Conclusion: Ces résultats indiquent qu 'au-delà des variables de personnalité, l'alcoolisme du père constitue un facteur de risque élevé en regard d'un problème de toxicomanie chez les jeunes. Toutefois, la supervision parentale permet d'atténuer ce risque, ce qui constitue un élément d'intervention important à considérer.

This study was conducted to verify the differential effects of content and method of delivery of training on trainers' management strategies and on the behaviors during training of boys who are inattentive, overactive, and aggressive (IOA). In the study, thirty 6-year-old boys identified as having IOA behaviors participated in 24 weekly social skills and self-regulation training sessions. They were divided into four subgroups matched on IQ, Preschool Behavior Questionnaire scores, and parent education level. Two trainers implemented the training with the four subgroups. Trainers' management strategies and the boys' behaviors during training were coded by independent observers. Results indicated that both trainers used more teaching management interventions (e.g., providing information and asking questions) and more behavior management interventions (e.g., calling the child to attention, recall of rules, formal interdictions) during the social skills training than during the self-regulation skills training. Boys had more difficulty sustaining their attention in social skills training than in self-regulation skills training. Implications for careful planning of content and delivery methods with regard to the particular behavioral and developmental needs of children exhibiting IOA behaviors are discussed.

METHODS: Data from a large longitudinal study of boys who were between kindergarten and age 13 years were used to (1) test whether Gray's and Cloninger's personality dimensions measured in kindergarten predicted the early onset of stable, highly delinquent behavior; (2) test whether 1, 2, or 3 dimensions were needed; and (3) test the predictive value of a categorical approach. RESULTS: The impulsivity dimension was the best predictor of the early onset of stable, highly delinquent behavior. Anxiety and reward dependence made significant but weaker contributions. The categorical approach corroborated Cloninger's suggestion that boys who are high in impulsivity, low in anxiety, and low in reward dependence would be more at risk for delinquent involvement. Boys who were high in impulsivity and low in anxiety but high in reward dependence were much less at risk for delinquency. Differences in antisocial behavior among extreme kindergarten personality groups were stable from ages 11 to 13 years. CONCLUSIONS: The behavioral activating system appears to be the major dimension underlying the propensity toward early onset of antisocial behavior, but both the behavioral inhibition system and the need for social rewards play important roles. The behavioral style (personality) that results from the interplay of these systems is clearly in place by the kindergarten year. Preventive efforts should target preschool children with at-risk behavior profiles. However, longitudinal-experimental studies with at least yearly assessments between birth and school-entry age are needed to understand the extent to which the behavioral styles are antecedent to preschool disruptive behavior disorders.

The purpose of the present experiment was to appraise the respective contribution of initial competence and of imitation of modeled response in the observational learning of conservation. Nonconservers were selected during a pretest: half succeeded and half failed an Anticipation Task. Anticipators and nonanticipators were subsequently exposed to one of five pretraining conditions which did not involve conservation: generalized imitation of modeled responses; generalized counterimitation; neutralization; contact with the pretraining setting; and no pretraining. Conservation was then demonstrated: one-third of the children were asked to repeat modeled responses during pauses in the demonstration; one-third rested during pauses; demonstration proceeded without pauses for the final third of the subjects. Posttesting was conducted immediately after and four weeks later. As predicted, performance of anticipators surpassed that of nonanticipators who showed no progress at all. Imitation pretraining provided optimal benefits. However, counterimitation pretraining did not prove detrimental as expected. Rehearsal manipulation, moreover, had no influence on acquisition. These results were discussed with reference to a hypothesized sequence of imitation and comprehension processes, the evolution of which is modified by the nonconserver's cognitive preparation and a situational encouragement of imitation.

Social problem-solving skills of aggressive-rejected children are usually assessed through hypothetical situations in a neutral setting where little or no reference is made to the emotional aspects. The aim of this study was to evaluate the social problem-solving skills of 57 aggressive-rejected (Group 1) and 57 prosocial-popular (Group 2) children of both sexes in Grades 1 and 2 by using as problem situations what happened in standardized provocations involving them with a trained peer-accomplice. An individual interview, aimed at disclosing emotions felt during the provocations, intentions attributed to the accomplice and possible reactions if confronted again with the same provocations, was conducted immediately after the session for half the subjects of each group. The other subjects were interviewed after a 10-min. delay. Analysis showed that Group 1 subjects would be less verbally assertive than Group 2 subjects if confronted again with the same provocations. The first graders from Group 1 also attributed fewer positive intents to the author of the provocations than Group 2 classmates. Second graders of both groups attributed more negative and fewer positive intents to the peer-accomplice when the interview immediately followed the provocations than when it was delayed. Similarly, second grade boys interviewed right away were more prone to use physical and verbal retaliation if the provocations were to happen again. These results highlight the influence of emotions on the social reasoning skills of aggressive-rejected and nonaggressive-nonrejected children.

Several studies of female adult populations suggest that somatization problems appear during adolescence and that they are related to behavioural problems during childhood. This study uses Cloninger's personality model to verify the link between personality traits and the beginning of somatization problems in elementary school girls. This model is based on the interaction of three dimensions: novelty seeking, harm avoidance and social reward dependence. Subjects were part of a longitudinal study of the social adjustment of children from Montreal and Val d'Or families. Evaluations of the girls' behaviour in kindergarten were used to establish personality types according to Cloninger's model. The somatization problems were assessed at age ten following interviews with mothers and girls, and ratings by mothers and teachers. The results showed that somatization problems at age ten were more likely when novelty seeking and harm avoidance were high in kindergarten. The kindergarten girls with ‘passive-aggressive’ or ‘explosive-schizoid’ personality profiles were more at risk of higher levels of somatization problems at age ten. However, Cloninger's hypothesized link between high levels of somatization problems and the ‘histrionic’ personality profile was not confirmed.

Consistency between teachers' and parents' ratings of 229 children's prosocial and problem behaviors was investigated from kindergarten through grade two. Intrarater stability was also analyzed. Results indicated moderate but decreasing interrater agreement from kindergarten to grade two for boys on externalizing behaviors. Interrater agreement for the same behavior dimension for girls was moderate and stable, whereas it was low on internalizing behavior problems and prosocial behaviors, for both genders throughout the 3-year period. Moreover, difference between teachers' and parents' ratings of externalizing behaviors increased from kindergarten to grade two. Decreasing level of agreement through time appeared to be related to a reduction of teacher-rated externalizing behaviors not paralleled by a reduction in parent ratings. Analyses were also performed at the item level of the externalization scale to identify which specific behaviors were responsible for the increasing divergence in interrater agreement from kindergarten through grade two. Alternative interpretations were considered in order to account for present and past results. Implications for screening and assessment purposes were discussed.