The development of peer victimization from 6 to 17 years of age : trajectories, antecedents and consequences in a longitudinal population-based birth cohort ; Le développement de l’intimidation par les pairs entre 6 et 17 ans : trajectoires, antécédents et conséquences en étude longitudinale populationnelle

Long considered by many as a rite of passage for school-aged children, peer victimization has become an important public health issue given its prevalence and serious impact on child mental health and well-being. Peer victimization is the experience of being the target of peers’ hostile behaviors intended to inflict physical harm or psychological distress. Across countries and cultures, one in three children reports victimization by peers at some point during their school years. About 5-15% of youth are exposed to chronic peer victimization and are at increased risk of mental health problems, including anxiety, depression and suicidality. To date, universal preventive interventions of peer victimization at the school level have shown significant but modest effects in reducing victimization. However, these interventions generally do not address individual or familial factors that may increase the likelihood of being a target of peers’ hostile behavior. Understanding the role such preexisting vulnerabilities play for subsequent peer victimization experiences may be particularly important during early childhood, a central period for social development and the initiation of peer relationships. Furthermore, the evidence on the development of peer victimization across childhood and adolescence including the association of its timing and intensity with mental health outcomes is scarce. This limits our understanding of the periods in child development that would be most appropriate for early prevention of peer victimization. The objectives of the current thesis were to examine (1) the developmental trajectories of peer victimization from 6 to 17 years of age; and its association with (2) a wide range of early childhood behaviors and socio-environmental factors and (3) mental health comorbidities in young adulthood. We used data from the Quebec Longitudinal study of Child Development, a population-based birth cohort of 2120 children followed-up yearly or every other year from birth to 20 years old. In Study 1, we ...