To go boldly where no scheme has been before : reconceptualising eating disorder diagnoses

Taking the weight criteria out of anorexia nervosa diagnostic features (Phillipou and Beilharz, 2018) is at first read a preposterous idea. Then I reread the paper and reconsidered. The authors argue that underweight as a mandatory diagnostic criterion overstates its utility and deemphasises more relevant features associated with severity, outcomes and recovery such as psychopathology and adaptive function. The authors have been bold and I’d suggest we should be bolder still. First, weight is a criterion for only one eating disorder, anorexia nervosa. All others are diagnosed according to core psychopathologies of disordered eating behaviours and/or cognitions. This causes confusion when people with binge eating and purging may not have a diagnosis of bulimia nervosa if they are underweight. As the authors note, the new ‘atypical anorexia nervosa’ diagnosis is also a state of severe weight loss and dietary restriction similar to anorexia nervosa, but people are at a normal or above normal weight. Does this happen? Well, yes and more often now the average weight of people in Australia is well above a body mass index (BMI; kg/m2) of 25. Thus, many people start weight loss at ever higher BMIs. In conclusion, I suspect the future is with the US National Institute of Mental Health Research Domain Criteria’s approach. This is to start anew and classify according to phenotypic groups of people with symptoms that are delineated on the basis of common biological/genetic, psychological and other defining features, and that transcend cultural ‘overlays’ such as thin idealisation. To further this, we need longitudinal studies of large community populations, that are representative of the vast majority of people with eating disorders who are not receiving an evidence-based treatment. This would have the added benefit of providing an opportunity to inform the treatment gap and how to close it, thereby reducing the huge community and personal burden from persistent eating disorders. With the government’s Million Minds’ call for research into eating disorders, we can dare to hope for a future with a new understanding of these problems, including but not limited to, how to classify them.