Characterizing eating disorder heterogeneity: Elucidating phenotypes through oculomotor responses and behavioural symptoms
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Authors
Kirkpatrick, Ryan Hannah
Date
2024-08-28
Type
thesis
Language
eng
Keyword
Eating Disorder , Eye Tracking , Self-Harm , Saccade , Eye Blink , Pupil , Psychiatry , Biomarker , Anorexia Nervosa , Bulimia Nervosa
Alternative Title
Abstract
Eating disorders are a group of psychiatric diagnoses characterized by pathologic behaviours surrounding food with a lifetime prevalence of 8.4% in females. Their onset is typically within adolescence or early adulthood and their impact has been on the rise since 2012. Despite this eating disorder pathophysiology remains largely unknown. This thesis presents a work aimed at exploring challenges surrounding biomarkers in psychiatry and improving the current understanding of eating disorder phenotypes through behavioural investigation focused on video-based eye tracking and meta-analysis. Chapter 2 presents a review on the methodological and clinical challenges impacting the search for biomarkers of psychiatric disease. Chapter 3 presents a systematic review and meta-analysis of 79 studies on the prevalence of non-suicidal self-injury in eating disorders. It was determined that non-suicidal self-injury has a prevalence of 34.6% in individuals with an eating disorder. Prevalence was found to vary between 21% and 42% in anorexia nervosa restrictive type, anorexia nervosa binge/purge type, bulimia nervosa, binge eating disorder and other specified feeding or eating disorder. Chapters 4 and 5 explore oculomotor behaviour among female youth (aged 10-25) with an eating disorder compared to sex-matched healthy controls. Chapter 4 assesses saccade, pupil and blink behaviour during a structured pro-saccade (rapid eye movement towards a stimulus) and anti-saccade (rapid eye movement away from a stimulus) task. Specifically, no differences were found in anti-saccade behaviours but individuals with an eating disorder made fixation breaks, anticipatory saccades and had a lower proportion of correct saccades. Individuals with an eating disorder also blink their eyes more between trials and had a smaller baseline pupil size. Chapter 5 explores saccade and pupil behaviours during an uninstructed video free-viewing task comparing food stimuli to control stimuli. Generally, behaviours did not differ between control and food clips. Individuals with an eating disorder made fewer saccades and fixate longer than controls. No differences were found between groups on blinking. Overall, this thesis provides a consolidation on non-suicidal self-injury in eating disorders and enriches the existing, yet sparse, literature on oculomotor behaviours in youth with an eating disorder, providing important insight into possible neural mechanisms involved.
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This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivatives 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivatives 4.0 International