An investigation into the prevalence of primary and secondary exercise addiction, their correlates, and detection

Introduction: Exercise addiction is a disorder where an exerciser loses control over exercise habits and acts compulsively, and can be a primary disorder, or secondary to an eating disorder. However, it is unknown if primary and secondary exercise addiction have different aetiologies. This thesis aims to examine differences between prevalence and correlates of primary and secondary exercise addiction and produces a novel screening tool for the detection of primary and secondary exercise addiction. Methods: Chapter 2 examines existing literature to determine if exercise addiction (a) exists in the absence of eating disorders, and (b) yields different prevalence rates in populations with-vs-without eating disorders. Chapter 3 examines differences between exercise motivations and body dysmorphic disorder in populations with-versus-without eating disorders. Chapter 4 describes the creation and validation of a questionnaire able to stratify people at risk of primary or secondary exercise addiction. Results: Chapter 2 reports that people with indicated eating disorders were 3.7 (95%CI 2.06.9) times more likely to be at risk of exercise addiction than people without indicated eating disorders. Chapter 3 reports that differing types of exercise motivation and body dysmorphic disorder were significant predictors of exercise addiction only in participants without indicated eating disorders (p=<0.05). These results suggest that primary and secondary exercise addiction have differing aetiologies, and the development of a tool able to stratify primary and secondary exercise addiction was warranted. Chapter 4 develops and pilots a new exercise addiction screening tool that was found to be reliable and valid. Conclusions: Exercise addiction appears to have differing aetiologies dependant on eating disorder status, which could have important implications for exercise addiction treatment. The Secondary Exercise Addiction Scale is a valid and reliable tool for simple stratification of primary and secondary exercise addiction, and could be used in several contexts, including in research and in practice.