Atypical anorexia nervosa: In need of further study.

In this issue of International Journal of Eating Disorders, Walsh et al. review the research to date comparing atypical anorexia nervosa (atypical AN) and AN. Most of the differences observed related to weight; eating disorder and noneating disorder psychopathology and complications were similar. The results could suggest that atypical AN and AN are not really different, and these findings should spur further research. Whether informative weight thresholds exist is a critical question. Beyond, why weight differs in these two groups is of great interest. If the two entities can be separated, does this separation predict longitudinal outcome or response to treatment? The high prevalence of atypical AN in clinical settings emphasizes the urgency of continuing research.