Development of Body Image and Eating Disorder Psychopathology: Normative and Pathological Trajectories

Abstract

Introduction: Body image is a critical area of wellbeing that predicts many important outcomes, including eating pathology. Unfortunately, there is no consensus about what constitutes normative body image development, or how people come to develop negative body image. The objective of this project was to advance understanding of both normative and pathological trajectories of body image and eating pathology development. Method: This dissertation includes a systematic review and meta-analysis (Chapter 2), and two primary longitudinal studies (Chapters 3 and 4). The meta-analysis summarized longitudinal data from 142 samples to characterize normative mean-level change in body image among females and males between ages 6 and 54. The two primary longitudinal studies took a person-centred approach to identify the most common trajectories of body image and eating pathology, and examine their predictors in two samples: a U.S. sample of 760 female twins assessed between ages 11 and 29; and a U.K. sample of 328 girls and 429 boys assessed between ages 11 and 15. Results: The meta-analysis identified gender-moderated patterns of normative body image development: boys showed small fluctuations in overall body image with net-improvements between ages 10 and 24, whereas girls showed worsening body image between ages 10 and 16, but improvements between ages 16 and 24. Mean-level changes were largest between ages 10 and 14, and stabilized by age 24. The two primary studies identified subgroups of boys and girls who deviated considerably from normative patterns of development; pathological subgroups showed greater proneness to stress, anxiety, and negative emotionality, social difficulties, dietary restraint, and lower global self-esteem. Conclusion: These studies advance theories of body image development. First, a critical period may occur slightly earlier than previously believed. Second, girls and boys may both, on average, experience improvements in body image during emerging adulthood. Third, pluripotent transdiagnostic risk factors such as personality characteristics merit increased attention alongside sociocultural variables that specifically increase risk for eating pathology.