Date of Award

Spring 2012

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Health Research Methodology

Supervisor

Peter Szatmari

Co-Supervisor

Michael Boyle

Language

English

Committee Member

Ellen Lipman

Abstract

This dissertation examined several dimensions of the development of physical aggression and indirect aggression in a longitudinal sample of boys and girls. These data are part of the National Longitudinal Study of Children and Youth which evaluated the development of children bi-annually from 1994 to 2010. The data for this thesis come from individuals aged 10 and 11 in Cycle 1 (1994) through to Cycle 5 (2002) when they were 18 and 19. In an attempt to explore trends in the development of aggression, the research is presented as three separate projects that examine the following: (1) measurement of physical and indirect aggression by informant and sex; (2) group-based trajectories of physical and indirect aggression and outcomes of trajectories in emerging adulthood; and (3) association between indirect aggression in adolescence and depression in emerging adulthood when physical aggression is taken into account. This is the first longitudinal study to investigate group-based physical and indirect aggression trajectories in childhood and adolescence and outcomes in emerging adulthood. The contribution of this thesis to the field of epidemiological research on aggression is the importance of considering distinct subgroups within both physical and indirect aggression, and joint trajectory groups of both physical and indirect aggression when exploring developmental trends and outcomes of aggression.

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