Eric Lacourse

Developmental trajectories of boys' delinquent group membership and facilitation of violent behaviors during adolescence

Being part of a delinquent group has been shown to facilitate the expression of an individuals 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 far 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-experimental approach to testing theories of antisocial behavior development.

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.

Heavy Metal Music and Adolescent Suicidal Risk

This study probes the differentiating characteristics (family relationships, social–psychological attitudes, drug use, and suicidal risk) of youth who prefer heavy metal (HM) music, worship music, and use music for vicarious release. Data analysis was based on a sample of 275 secondary school students between the ages of 14 and 18. Logistic regressions revealed that HM music preference and worshipping is not significantly related to suicidal risk when controlling for other risk factors. These findings were found for both boys and girls. Surprisingly, the use of music for vicarious release was inversely related to suicidal risk for girls. These findings are discussed within the framework of Arnetts alienation theory (Arnett, J. (1991). J. Youth Adolesc. 20(6): 573–592) and Roes uses-gratification theory (Roe, K. (1995). J. Youth Adolesc. 24(5): 617–631) regarding adolescent socialization and media purposes.

Neighborhood poverty and suicidal thoughts and attempts in late adolescence

BACKGROUND Suicide tends to concentrate in disadvantaged neighborhoods, and neighborhood disadvantage is associated with many important risk factors for youth suicide. However, no study has directly investigated the link between neighborhood poverty and youth suicidal behaviors, while controlling for pre-existing vulnerabilities. The objective of this study was to determine whether living in a poor neighborhood is associated with suicidal thoughts and attempts in late adolescence over and above background vulnerabilities, and whether this association can be explained by late-adolescence psychosocial risks: depression, social support, negative life events (NLEs), delinquent activities, substance abuse and exposure to suicide. The potential moderating role of neighborhood poverty was also examined. METHOD A subset of 2776 participants was selected from the Canadian National Longitudinal Survey of Children and Youth (NLSCY). Late-adolescence suicidal behaviors and risk factors were self-reported. The 2001 Canadian Census was used to characterize neighborhoods during early and middle adolescence. Late-childhood family and individual controls were assessed through parent-report. RESULTS At the bivariate level, the odds of reporting suicidal thoughts were about twice as high in poor than non-poor neighborhoods, and the odds of attempting suicide were about four times higher. After controlling for background vulnerabilities, neighborhood poverty remained significantly associated with both suicidal thoughts and attempts. However, these associations were not explained by late-adolescence psychosocial risks. Rather, youth living in poor neighborhoods may be at greater risk through the amplification of other risk factors in disadvantaged neighborhoods. CONCLUSIONS Potential explanations for the increased vulnerability of youth living in poor neighborhoods are discussed.

Parental practices in late adolescence, a comparison of three countries: Canada, France and Italy

The objective of this study was to examine parental practices, such as affection, control and conflict, in three countries: Canada, France and Italy. The sample was composed of more than 900 late adolescents with an average age of 17 years, from three large cities: Montreal, Paris and Rome. Participants answered a self-report questionnaire that assessed five measures: emotional bonds with the father and mother, parental supervision, tolerance towards friends, punitiveness for violation of rules, and conflict frequency. Analyses of the results indicated that the country of origin discriminated for most of the parental practice dimensions. Canadian adolescents considered their parents to be more tolerant and rated them as using less punitive measures when rules were broken. Canadian parents also seemed to adopt comparable norms for boys and girls, which could be interpreted as a form of sexual egalitarianism, whereas Italian and French parents appeared less tolerant towards girls. Italian adolescents reported strong emotional bonds with each parent, and also identified more conflicts in their relationships with parents. French adolescents reported weaker emotional bonds with each parent and less parental supervision. Results were interpreted in the light of studies that have reported an influence of cultural background on both parental practices and parental decisions in each of these countries.

Testing the Developmental Distinctiveness of Male Proactive and Reactive Aggression With a Nested Longitudinal Experimental Intervention

An experimental preventive intervention nested into a longitudinal study was used to test the developmental distinctiveness of proactive and reactive aggression. The randomized multimodal preventive intervention targeted a subsample of boys rated disruptive by their teachers. These boys were initially part of a sample of 895 boys, followed from kindergarten to 17 years of age. Semiparametric analyses of developmental trajectories for self-reported proactive and reactive aggression (between 13 and 17 years of age) indicated three trajectories for each type of aggression that varied in size and shape (Low, Moderate, and High Peaking). Intent-to-treat comparisons between the boys in the prevention group and the control group confirmed that the preventive intervention between 7 and 9 years of age, which included parenting skills and social skills training, could impact the development of reactive more than proactive aggression. The intervention effect identified in reactive aggression was related to a reduction in self-reported coercive parenting. The importance of these results for the distinction between subtypes of aggressive behaviors and the value of longitudinal-experimental studies from early childhood onward is discussed.

Neighborhood Poverty and Early Transition to Sexual Activity in Young Adolescents: A Developmental Ecological Approach.

This study examined how the link between neighborhood poverty and the timing of sexual initiation varies as a function of age, gender, and background characteristics. A sample of N = 2,596 predominately White Canadian adolescents from the National Longitudinal Survey of Children and Youth was used. Sexual initiations occurring between 12 and 15 years old were considered. Results showed that younger adolescent females who lived in poor neighborhoods and who had a history of conduct problems were more likely to report early sexual activity. Peer characteristics partly accounted for this susceptibility. Among adolescent males, no direct neighborhood effects were found, but those who had combined risks at multiple levels appeared more vulnerable. The theoretical and practical implications of these findings are discussed.

Antecedents and outcomes of joint trajectories of mother-son conflict and warmth during middle childhood and adolescence

This study investigated the development of mother-son relationship quality from ages 5 to 15 in a sample of 265 low-income families. Nonparametric random effects modeling was utilized to uncover distinct and homogeneous developmental trajectories of conflict and warmth; antecedents and outcomes of the trajectory groups also were examined. Four conflict trajectory groups and 3 warmth trajectory groups were identified. Difficult temperament in early childhood discriminated both conflict and warmth trajectory group membership (TGM), and adult relationship quality in early childhood was related to warmth trajectories. In addition, conflict TGM differentiated youth antisocial behavior during adolescence, and warmth trajectories predicted adolescent peer relationship quality and youth moral disengagement. Implications for socialization processes are discussed.

Childhood hyperactivity, physical aggression and criminality: a 19-year prospective population-based study

Background Research shows that children with Attention Deficit/Hyperactivity Disorder are at elevated risk of criminality. However, several issues still need to be addressed in order to verify whether hyperactivity in itself plays a role in the prediction of criminality. In particular, co-occurrence with other behaviors as well as the internal heterogeneity in ADHD symptoms (hyperactivity and inattention) should be taken into account. The aim of this study was to assess the unique and interactive contributions of hyperactivity to the development of criminality, whilst considering inattention, physical aggression and family adversity. Methodology/Principal Findings We monitored the development of a population-based sample of kindergarten children (N = 2,741). Hyperactivity, inattention, and physical aggression were assessed annually between the ages of 6 and 12 years by mothers and teachers. Information on the presence, the age at first charge and the type of criminal charge was obtained from official records when the participants were aged 25 years. We used survival analysis models to predict the development of criminality in adolescence and adulthood: high childhood hyperactivity was highly predictive when bivariate analyses were used; however, with multivariate analyses, high hyperactivity was only marginally significant (Hazard Ratio: 1.38; 95% CI: 0.94–2.02). Sensitivity analyses revealed that hyperactivity was not a consistent predictor. High physical aggression was strongly predictive (Hazard Ratio: 3.44; 95% CI: 2.43–4.87) and its role was consistent in sensitivity analyses and for different types of crime. Inattention was not predictive of later criminality. Conclusions/Significance Although the contribution of childhood hyperactivity to criminality may be detected in large samples using multi-informant longitudinal designs, our results show that it is not a strong predictor of later criminality. Crime prevention should instead target children with the highest levels of childhood physical aggression and family adversity.

A longitudinal twin study of physical aggression during early childhood: evidence for a developmentally dynamic genome.

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. METHOD Participants were 667 twin pairs, including 254 monozygotic and 413 dizygotic pairs, from the ongoing longitudinal Quebec Newborn Twin Study. Maternal reports of PA were obtained from three waves of data at 20, 32 and 50 months. These reports were analysed using a biometric Cholesky decomposition and linear latent growth curve model. RESULTS The best-fitting Cholesky model revealed developmentally dynamic effects, mostly genetic attenuation and innovation. The contribution of genetic factors at 20 months substantially decreased over time, while new genetic effects appeared later on. The linear latent growth curve model revealed a significant moderate increase in PA from 20 to 50 months. Two separate sets of uncorrelated genetic factors accounted for the variation in initial level and growth rate. Non-shared and shared environments had no effect on the stability, initial status and growth rate in PA. CONCLUSIONS Genetic factors underlie PA frequency and stability during early childhood; they are also responsible for initial status and growth rate in PA. The contribution of shared environment is modest, and perhaps limited, as it appears only at 50 months. Future research should investigate the complex nature of these dynamic genetic factors through genetic-environment correlation (r GE) and interaction (G×E) analyses.