Une étude génétiquement informative du développement de l’agression durant l’enfance et de l’influence des pratiques parentales coercitives

Interpersonal violence has significant negative impacts on the health and well-being of individuals. Aggression is increasingly conceptualized using a dimensional perspective in which the forms of functions are separated. In terms of functions, the literature distinguishes between proactive and reactive aggression. The former are committed with a specific purpose and can take the form of a physical aggression such as a punch or the form of a social aggression such as bullying. Reactive aggression is defensive and aim to respond to one or more actions that were perceived as hostile. Behavior genetics research shows that an important part of the inter-individual differences in the use of aggression may be associated with genetic factors. The relative importance of genetic and social factors in the explanation of behavior is important for the development of sociological theories. The general objective of this thesis is to describe the genetic and environmental etiology of the development of proactive and reactive aggression during childhood. Developing more specific theories of the development of aggression can help school and health systems work toward reducing the use of interpersonal violence. To this end, a longitudinal sample of twins is used for the three specific objectives covered by the empirical articles. The aim of the first article is to describe the genetic and environmental etiology of the co-occurrence of the two functions of aggression during childhood. The second article aims to describe the genetic and environmental etiology of the development of the two functions of aggression. Finally, the third article look into with the influence of coercive parenting on the development of aggression. Together, these articles highlight several important nuances regarding the factors associated with the development of aggression during childhood. The first article shows that the functions of aggression share important genetic factors and that these have a lasting and dynamic influence. In addition, specific genetic factors are associated with reactive aggression. The second article shows the common genetic factors are associated with the initial level of the average trajectory of the two functions of aggression. Finally, the third article shows that an important part of the effect of coercive parenting on the development of aggression corresponds to an evocative correlation between genes and the environment. This type of correlation suggests that parents react to their child's genetically influenced characteristics. However, there is no indication of a similar pattern for reactive aggression. It thus seems important to consider individual differences influenced by genetics in the development of aggression as well as a better match between a target audience and each intervention program to increase their effectiveness. Also, research about the genetic characteristics specific to reactive aggression could help identify the children struggling with this problem and help clinicians use appropriate interventions. It also seems that the prevention of coercive parenting could have a positive impact on the prevention of proactive aggression in children.

Keyphrases: coercition, Proactive aggression, Reactive aggression, Development, Trajectory