The "Transdiagnostic" View of Eating Disorders

For the past decade there has been debate in the eating disorders research community about the relevance of eating disorders being divided into separate diagnostic categories.

On one side of the debate, Christopher Fairburn, Zafra Cooper and Roz Shafran (2003) at Oxford University have proposed that current eating disorder classifications should be re-evaluated because they have been divided arbitrarily in a way that does not reflect the actual experience of people with eating disorders. The Oxford team describe how anorexia, bulimia and other eating disorders have more features in common than separate them. At the core of most eating disorders, they propose, is the individual's over-evaluation of the control of weight, shape and/or eating. Symptoms such as binge eating, purging, rigid dieting and adherence to strict eating rules may occur for people with any of the eating disorders. Likewise, emotional states such as anxiety, guilt, low self-esteem, and preoccupation with food are experienced by most people with eating disorders, regardless of their specific diagnosis. The Oxford team also recognises that a significant proportion of people with eating disorders find that over time their eating behaviours (and hence their diagnosis) may change but their concerns about eating and weight endure unchanged. For these reasons, the Oxford team have suggested that a better way of developing effective treatments for eating disorders is to see the various symptoms as manifestations of a more broadly defined "eating disorder" (hence the term, "transdiagnostic") and to focus on understanding and working with the common underlying processes. They have also acknowledged that previous forms of CBT for eating disorders were insufficiently potent in helping people overcome bulimia and did not help people with anorexia. The transdiagnostic CBT treatment includes modules on helping people with anorexia to gain weight, plus modules to address common impediments to recovery including body image preoccupation, perfectionism, low self-esteem, interpersonal problems and mood intolerance.

On the other side of the debate, concerns have been raised about the possible effects of eating disorders being merged into one broad diagnostic group. For instance, C. Laird Birmingham, Stephen Touyz and Jane Harbottle (2009), researchers from Canada and Australia, have noted that anorexia has the highest mortality rate of all mental health diagnoses. If the diagnosis of anorexia is "lost," the associated death and disability statistics will be watered down, which may result in reduced funding for specialist treatment which is already inadequate in most areas. They argue that, rather than anorexia and bulimia both being rooted in the over-evaluation of control of weight, shape and/or eating, they have distinctly different causes and should be treated differently. The strongest evidence for this is that there appears to be different genetic predispositions for anorexia and bulimia. Research to date shows the most effective treatment for bulimia is CBT and antidepressants but anorexia is best treated with weight restoration and psychological therapy, however there is insufficient evidence to suggest that any particular type of therapy is superior.

References

Birmingham, C.L., Touyz, S. & Harbottle, J. (2009). Are anorexia nervosa and bulimia nervosa separate disorders? Challenging the 'transdiagnostic' theory of eating disorders. European Eating Disorders Review, 17, 2-13.

Fairburn, C.G., Cooper, Z. & Shafran, R. (2003). Cognitive behaviour therapy for eating disorders: a "transdiagnostic" theory and treatment. Behaviour Research and Therapy, 41, 509-528.