Eighty-five per cent of what? Discrepancies in the weight cut-off for anorexia nervosa substantially affect the prevalence of underweight

Department of Psychology, Yale University, New Haven, CT, USA.
Psychological Medicine (Impact Factor: 5.94). 09/2008; 39(5):833-43. DOI: 10.1017/S0033291708004327
Source: PubMed


DSM-IV cites <85% of expected body weight (EBW) as a guideline for the diagnosis of anorexia nervosa (AN) but does not require a specific method for calculating EBW. The purpose of the present study was to determine the degree to which weight cut-off calculations vary across studies, and to evaluate whether differential cut-offs lead to discrepancies in the prevalence of individuals who are eligible for the AN diagnosis.
Two coders independently recorded the EBW calculation methods from 99 studies that either (a) compared individuals with AN to those with subclinical eating disorders or (b) conducted AN treatment trials. Each weight cut-off was applied to a nationally representative (n=12001) and treatment-seeking (n=189) sample to determine the impact of EBW calculation on the proportion who met the AN weight criterion.
Coders identified 10 different EBW methods, each of which produced different weight cut-offs for the diagnosis of AN. Although only 0.23% of the national sample met the lowest cut-off, this number increased 43-fold to 10.10% under the highest cut-off. Similarly, only 48.1% of treatment seekers met the lowest cut-off, whereas 89.4% met the highest.
There is considerable variance across studies in the determination of the AN weight cut-off. Discrepancies substantially affect the proportion of individuals who are eligible for diagnosis, treatment and insurance reimbursement. However, differences may not be fully appreciated because the ubiquitous citation of the 85% criterion creates a sense of false consensus.

Full-text preview

Available from:

  • No preview · Article · Feb 2009 · Alternative and Complementary Therapies
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Eating disorder not otherwise specified (EDNOS) is the most prevalent eating disorder (ED) diagnosis. In this meta-analysis, the authors aimed to inform Diagnostic and Statistical Manual of Mental Disorders revisions by comparing the psychopathology of EDNOS with that of the officially recognized EDs: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). A comprehensive literature search identified 125 eligible studies (published and unpublished) appearing in the literature from 1987 to 2007. Random effects analyses indicated that whereas EDNOS did not differ significantly from AN and BED on eating pathology or general psychopathology, BN exhibited greater eating and general psychopathology than EDNOS. Moderator analyses indicated that EDNOS groups who met all diagnostic criteria for AN except for amenorrhea did not differ significantly from full syndrome cases. Similarly, EDNOS groups who met all criteria for BN or BED except for binge frequency did not differ significantly from full syndrome cases. Results suggest that EDNOS represents a set of disorders associated with substantial psychological and physiological morbidity. Although certain EDNOS subtypes could be incorporated into existing Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) categories, others-such as purging disorder and non-fat-phobic AN-may be best conceptualized as distinct syndromes. (PsycINFO Database Record (c) 2009 APA, all rights reserved).
    Full-text · Article · Jun 2009 · Psychological Bulletin
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Current diagnostic criteria for anorexia nervosa (AN) and bulimia nervosa (BN) account for a minority of individuals with clinically significant disorders of eating, raising concerns about the clinical utility of current definitions. This review examines evidence for the validity of current and alternative approaches to defining eating disorders and implications for draft criteria for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Although this review largely supports the predictive validity of distinctions among AN, BN, and the newly proposed binge eating disorder (BED), it also highlights that our tendency to "study what we define" has created a gap between the problems that people have and what we know about those problems. Future research on the causes and consequences of eating disorders should include more heterogeneous groups to enable identification of meaningful boundaries that distinguish between disorders based on etiological and predictive validity.
    Full-text · Article · Apr 2011 · Annual Review of Clinical Psychology
Show more