Atypical anorexia nervosa: separation from typical cases in course and outcome in a long-term prospective study

To assess differences in long-term course and outcome between typical and atypical cases of anorexia nervosa.

A naturalistic, longitudinal prospective design was used to assess recovery, relapse, and onset of binge eating over 10 to 15 years in patients ascertained through a university-based specialty treatment program. Atypical anorexia nervosa was distinguished from the diagnostically prototypic form of the disorder based on the continuous absence of morbid fear of weight gain and body size distortion during the inpatient phase of treatment. Patients were assessed semiannually for 5 years then annually thereafter until the final visit.

Compared to pure cases of anorexia nervosa, atypical cases were less likely to drop weight after discharge, recovered more rapidly, and had lower cumulative risk for developing binge eating.

It has been argued recently that weight phobia and body image disturbance should not be viewed as critical to the diagnosis of anorexia nervosa. This study shows that the absence of these particular symptoms in patients presenting with malnutrition secondary to extreme dietary restriction predicts a less malignant course and outcome compared to typical cases of anorexia nervosa. These course differences suggest that the division of patients into typical versus atypical diagnostic subtypes may be nosologically valid and clinically useful.