Stress and the development of disordered eating in rats

Hancock, Stephanie D. (2009) Stress and the development of disordered eating in rats. Doctoral (PhD) thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (11MB)

Abstract

Development of an eating disorder involves an interplay of factors, which may be environmental, biological, developmental, genetic, and/or psychological. All eating disorders are more prevalent in females, have an increased propensity for adolescent onset, and are, in most instances, precipitated by stressful life events. The value inherent in using an animal model to investigate the etiology of disordered eating lies in the real-life validity of such a model. Despite clinical evidence that early-life stress and heightened anxiety frequently precede the onset of pathological eating, animal models of eating disorders have not incorporated these findings to any great extent. Nor do most models take into account that the largest population of eating-disordered individuals is comprised of adolescent females and young women. The goals of this thesis were: (i) to present an overview of the physiological mechanisms that underlie stress-induced alterations in feeding systems and eating behaviours; and (ii) to examine potential factors that influence susceptibility to develop binge eating and anorexia using the most well-established animal models of these disorders. The research presented demonstrates that low levels of maternal care in early life are associated with greater vulnerability to the later development of stress-induced binge eating of highly-palatable food and, further, that this heightened vulnerability manifests in females during adolescence. In an activity-based animal model of anorexia nervosa (ABA), young adult animals that experienced early-life maternal separation lost weight faster, ate less, ran more, and required fewer days to reach removal criterion compared to their handled counterparts, with females, in particular, showing increased vulnerability. Finally, using a milder version of the ABA paradigm, early-life maternal separation increased females' susceptibility to ABA during adolescence, but not in adulthood, whereas males' susceptibility to ABA was increased only in adulthood. Together, these findings highlight the interplay between environmental, biological, and developmental factors in the etiology of binge eating and ABA.

Actions (login required)

View Item