Negative affect, isolation and menstrual cycle as antecedents of eating in individuals with disordered eating : an ecological momentary assessment study
Disordered eating (DE) is a subclinical eating disorder that includes a wide range of unhealthy behaviours, spanning from occasional dieting and use of laxatives to chronic dieting that may eventually evolve into a clinical eating disorder. Several studies indicate that disordered eating is associated with distress and impairment, underscoring the need for intervention, as it is the most common indicator of the development of an eating disorder. However, little is known about factors that trigger and maintain disordered eating behaviours. For example, the literature supports the possible role of a dysfunctional attachment style, as well as proximal negative affect and immediate context, in precipitating disordered eating behaviours. Moreover, hormonal changes seem to be responsible for exacerbating disordered eating symptomatology in accordance with a particular phase of the menstrual cycle (e.g., prior to or during menstruation). This dissertation examined the role of attachment style, negative affect, immediate context and menstrual cycle as possible antecedents of eating in disordered and normal eaters. Longitudinal changes one-hour prior to and after eating, and over a one-week period have been investigated. Moreover, the influence of menstrual cycle on eating intake in the disordered eating sample and general population has been studied. The research utilised Ecological Momentary Assessment (EMA), a design that involved repeated assessments of current psychological and situational states in participants' natural environments. Forty-six male (Mean = 28.8 years old) and ninety female participants (Mean = 28.7 years old) with disordered eating (N = 55) and healthy controls (N = 81) were recruited from the community to make multiple daily ratings of affect, hunger levels, menstrual status (for the female sample), time and location using random-, interval-, and event-contingent recordings. They had to record their food intake, mood and location over a one-week period, to investigate their eating pattern, and over a two-week period to study the impact of menstrual cycle on eating behaviours. Hierarchical regressions, Generalised Estimating Equations, repeated-measured Manova/Anova and Mixed Model analyses were used to examine between-day differences and within-day changes in psychological, situational variables relative to eating and menstrual status in disordered eating individuals and controls. The results showed that the feeling of loneliness might predict disordered eating behaviours when moderated by an anxious attachment style [B (SE) = -1.62, p = .029)]. Levels of shame [Estimate (SE) = -.483 (.222), p = .030] and disgust [Estimate (SE) = -.428 (.177), p = .016] were higher at eating episodes, while guilt [Estimate (SE) =.639 (.189), p = .001] increased mostly after eating. Moreover, the results confirmed the importance of situational factors in precipitating disordered eating behaviours [e.g., being at home [OR (95%IC) = .847 (.753-.952), p =. 005], absence of others [OR (95%IC) = .883 (.786-.993), p = .037)]. This is the first study to demonstrate that there are within-person situational processes in disordered eating revealing that the absence of others might be a unique antecedent of eating pathology. In addition, loneliness, shame, disgust and guilt might play a unique role in triggering and maintaining disordered eating. Menstrual cycle seemed to play an important role in influencing eating pattern in disordered eating individuals. Disordered eating females experienced cravings (F = 41.25, p < .001) and bloating (F = 3.39, p < .001) more frequently on menstrual days compared to non-menstrual days, while controls did not show much difference. To conclude, findings suggest that the absence of others, high levels of negative affect and the menstrual cycle might precipitate disordered eating behaviours in a subclinical disordered eating population.