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.