Examining the utility of narrowing anorexia nervosa subtypes for adults

The purpose of this investigation was to examine whether narrowing the criteria of anorexia nervosa (AN) subtypes among adults based on further delineations of current binge eating and purging (i.e., binge eating only, purging only, binge eating and purging, and restricting only) improves the potential clinical utility of the current DSM-5 system that specifies two types (i.e., current binge eating and/or purging and restricting, specified as the absence of current binge eating and/or purging).

Self-reported eating disorder and psychiatric symptoms based on the Eating Disorder Questionnaire were examined in 347 adults from a multisite clinical sample who met DSM-IV criteria for AN. Classification based on binge eating and purging symptoms yielded the following subtypes: 118 restricting only (AN-R; no current binge eating or purging); 133 binge eating and purging (AN-B & P; current binge eating and purging); 43 binge eating only (AN-B; current binge eating and no current purging); and 53 purging only (AN-P; current purging and no current binge eating).

The AN-R group had lower current body mass index compared to AN-B & P and AN-P with no group differences in highest, lowest, or desired body mass index. The probability of amenorrhea was higher for the AN-R and AN-B & P groups than the AN-P group. The probability of diet pill use was elevated for the AN-B & P and AN-P groups compared to the AN-R group. The AN-P group also had a higher probability of fasting than the AN-R group. The probability of substance use including tobacco was lower in the AN-R group than the other three groups. No group differences were found on measures of hospitalization, body image, physical symptoms, exercise, or dieting behaviors.

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 given that few differences were found among groups who reported any combination of current binge eating and purging. Future research is needed to replicate these findings and to further examine the AN subtype classification schemes.