Atypical anorexia nervosa is a subtype of other specific eating or eating disorders (OSFED). A person with atypical anorexia nervosa will meet all criteria for anorexia nervosa; however, despite significant weight loss, the person's weight is within or above the normal BMI range. Atypical anorexia nervosa is serious and life-threatening, and will have effects and complications similar to those of anorexia nervosa. People with eating disorders may have a variety of symptoms.
Common symptoms include severe food restriction, binge eating, and purging behaviors, such as vomiting or excessive exercise. One consideration is that the criterion for restricting the subtype stipulates that those in this subgroup will not have “regular binge eating or purging behavior.” By extension, it is also unclear what period of time must elapse before a subtype can be considered to have changed, since it is clear that patients can change subtype diagnoses over time, as will be discussed below. However, when considering the literature, it is important to note that descriptions of what constitutes these subtypes have been inconsistent. It is not clear that the definitions given in the DSM-IV allow physicians to reliably distinguish between the restrictive subtype and the compulsive purge subtype.
These findings do not support the validity or clinical utility of classifying AN into narrower subtypes based on current binge eating, purging, and binge eating with purging, as little difference was found between groups reporting any combination of current binge eating and purging. Future research is needed to replicate these findings and further examine subtype classification schemes of AN. People with this disorder have symptoms similar to those of bulimia or the subtype of binge eating anorexia. Most research in this area suggests that the designation of an individual's diagnostic subtype may change over time and that the most common patterns of crossing are from the AN restrictor type to the AN type of compulsive purging, and from compulsive purging AN to BN.
These four questions are relevant to deciding whether the AN subtyping scheme should be kept as is, deleted or modified in the next version of the DSM. Narrow subtypes were created based on the appearance of any self-reported symptoms of binge eating and purging in the past month. This movement between diagnoses or diagnostic subtypes is called diagnostic crossover and is especially common in people with anorexia nervosa. Anorexia is officially classified into two subtypes: the restrictive type and the type of binge eating and purging (.
The literature was reviewed, including studies comparing individuals with subtype diagnoses in clinical and outcome variables, as well as more recent research examining the frequency of crossover of diagnoses.