The validity and utility of subtyping bulimia nervosa

Objective: To review the evidence for the validity and utility of subtyping bulimia nervosa (BN) into a purging (BN‐P) and a nonpurging subtype (BN‐NP), and of distinguishing BN‐NP from binge eating disorder (BED), by comparing course, complications, and treatment. Method: A literature search of psychiatry databases for studies published in peer‐reviewed journals that used the DSM‐definitions of BN and BED, and included both individuals with BN‐NP and individuals with BN‐P and/or BED. Results: Twenty‐three studies compared individuals with BN‐NP ( N = 671) to individuals with BN‐P ( N = 1795) and/or individuals with BED ( N = 1921), two of which reported on course, 12 on comorbidity and none on treatment response—the indicators for validity and clinical utility. The differences found were mainly quantitative rather than qualitative, suggesting a gradual difference in severity from BN‐P (most severe) through BN‐NP to BED (least severe). Discussion: None of the comparisons provided convincing evidence for the validity or utility of the BN‐NP diagnosis. Three options for the position of BN‐NP in DSM‐V were suggested: (1) maintaining the BN‐NP subtype, (2) dropping nonpurging compensatory behavior as a criterion for BN, so that individuals currently designated as having BN‐NP would be designated as having BED, and (3) including BN‐NP in a broad BN category. © 2009 American Psychiatric Association. Int J Eat Disord 2009