Abstract

Introduction: Diagnostic systems conceptualise different eating disorders as discrete entities, identified at a particular point in time. However, research shows there is much overlap between ‘anorexia’ and ‘bulimia’, and the most prevalent diagnosis is ‘Eating Disorder Not Otherwise Specified’ (EDNOS), when people fail to meet full criteria for other diagnoses (Fairburn & Bohn, 2005). When considered from a longitudinal perspective, eating disorder diagnoses and behaviours also tend to change over time, a phenomenon called ‘diagnostic crossover’.
Although it is accepted that the prevalence of ‘diagnostic crossover’ in eating disorders is high (e.g. Eddy et al., 2002), the process through which it occurs is poorly understood. Authors have suggested that higher movement from ‘anorexia’ into ‘bulimia’ may represent an inability to maintain restrictive eating and have deliberated about a ‘natural course’ to the eating disorders. Although physiological and psychological effects of starvation suggest this may play a part (Polivy, 1996), some people avoid diagnostic crossover and others move from ‘bulimia’ into ‘anorexia’, which suggests additional factors are involved. Other researchers have proposed that clinical and personality variables such as low self directedness influence these transitions (Tozzi et al., 2005), but the results are inconsistent.
Eating disorder therapies are underpinned by psychological models, but these are theorised on the basis of eating disorder diagnoses, which for the reasons above may be invalid, and ignore transitions between them. Although some theories acknowledge crossover (e.g. Fairburn, Cooper & Shafran, 2003), they fail to fully account for the process. Since anorexia binge-purge type, and therefore the acquisition of more eating disorder behaviours, is often associated with poorer outcomes (e.g. Carter et al., 2012, Favaro & Santonastaso, 1996, Herzog, Schellberg & Deter,1997), better understanding of the way eating disorders change over time could improve outcomes and quality of life for patients.
Objectives:To investigate the experience of diagnostic crossover, which will be referred to as ‘eating disorder transitions’ to represent the phenomenon as a process rather than a discrete event. This aims to gain a better understanding of the process through which this occurs, and improve insight into the trajectory of eating disorders to further our understanding of them.
Methods: Twelve people with a history of transitioning between ‘anorexic behaviours’ (more restrictive eating) and ‘bulimic behaviours’ (bingeing and/or purging) were interviewed about the experience. The results were analysed using ‘Thematic Analysis’.
Results and Discussion: Participants’ eating disorders tended to focus on restrictive eating before cycles of bingeing and purging developed in a staged process. The effects of certain life experiences either triggered a change, or facilitated the emergence of these different eating disorder behaviours. When the expression of eating disorders was inhibited and underlying emotional difficulties remained, the eating disorder changed to a different form to compensate. Since participants continually valued being thin, bingeing and purging behaviours were evaluated much more negatively than phases of restrictive eating and led to risky behaviours. The findings suggest that attempts to change eating disorder behaviours without helping patients manage their underlying difficulties first should perhaps be avoided.