How to determine the capacity of a person diagnosed with anorexia to refuse medical treatment has been called the ‘hard case’ of capacity law. I demonstrate that courts have used a process of circular reasoning when making this determination, where treatment refusals are simultaneously used as evidence of cause (anorexia) and effect (incapacity). This reasoning means that anyone with the diagnosis of anorexia will be found to lack capacity to refuse its treatment. The circular reasoning has a negative effect on the law, and means that indicia of capacity that ought to be considered by the court can be ignored. The result is a procedure in which the person diagnosed with anorexia has no voice, and an outcome against which he or she has no effective legal recourse.
I argue that this problem can be mitigated in two ways. Firstly, courts must make sure that the ‘functional’ test of capacity is properly applied, meaning any finding of incapacity must rest on evidenced deficits in decision-making ability. Secondly, courts must properly engage with the subjective reasoning of the person making the treatment refusal.