1. Objectifs

Intentions :
Cette recherche aborde la propagation des comportements problématiques dans des dyades de jumeaux en abordant la consommation de drogue et la délinquance.

2. Méthode

Échantillon/Matériau :
«The 628 participants (302 boys, 326 girls) belonged to 179 MZ [monozygotic] and 135 same-sex DZ [dizygotic] twin pairs, drawn from the Quebec Newborn Twin Study, an ongoing longitudinal study of a population-based sample of twins born between 1995 and 1998 in the greater Montreal area.» (p. 331)

Type de traitement des données :
Analyse statistique

3. Résumé

«As expected, there was evidence that problems spread between twins. However, problems did not spread directly between twins across domains of misconduct. Instead, problems spread indirectly via two two-step processes: (a) interindividually (between twins) within a behavioral domain, then intraindividually (within twins) across behavioral domains […] or (b) intraindividually (within twins) across behavioral domains, then interindividually (between twins) within a behavioral domain […].» (p. 334-335) «Our findings are consistent with results indicating that sibling resemblance in problem behaviors cannot be entirely explained by genetics or shared environments […]. In the present study, sibling effects emerged in APIM [actor–partner interdependence model] analyses, over and above the modest to moderate genetic and shared environmental contributions to substance use and delinquency that were identified in the quasi-ACE [adaptive coping with emotions] model. [Results also] suggest indirect sibling transmission of behavior problems; problems spread between siblings within domains, which implies that problems can be arrested with interventions that disrupt the behavior not the relationship.» (p. 335)