Validity and utility of subtyping anorexia nervosa.

OBJECTIVE: The purpose of this article is to review the available literature that addresses the predictive validity and utility of subtyping patients with anorexia nervosa (AN) into binge/purge and restrictor subtypes.
METHOD: Literature was reviewed including studies that compared individuals with subtype diagnoses on clinical and outcome variables as well as more recent research examining the frequency of diagnostic crossover.
RESULTS: Several studies found that in general the binge/purge subtype patients have more psychopathology, tend to be older, and tend to have a worse outcome. More recent studies which have examined diagnostic crossover suggest that the rate of crossover from the restrictor subtype to the binge/purge subtype is substantial. Crossover from the binge/purge to the restrictor subtype appears to occur less commonly. There is also literature documenting crossover from AN to bulimia nervosa (BN) and a small literature looking at crossover from BN to AN. DISCUSSION: The results of this article suggest that although there is generally progression from restrictor AN to binge/purge AN to BN in a sizeable number of patients, other crossover patterns can be seen as well and the amount of crossover is quite large. This suggests a lack of predictive validity for subtypes.