Eating disorder not otherwise specified
|Eating Disorder Not Otherwise Specified (EDNOS)|
|Classification and external resources|
Eating disorder not otherwise specified (EDNOS) is an eating disorder that does not meet the criteria for anorexia nervosa or bulimia nervosa. Thus, individuals who have clinically significant eating disorders that do not meet DSM-V criteria for anorexia nervosa or bulimia nervosa are diagnosed with EDNOS. Individuals with EDNOS usually fall into one of three groups: subthreshold symptoms of anorexia nervosa or bulimia nervosa, mixed features of both disorders, or extremely atypical eating behaviors that are not characterized by either of the other established disorders.
Many people think that this type of eating disorder is not as serious compared to anorexia and bulimia. However, that is not the case because more people are diagnosed with EDNOS than anorexia and bulimia combined. Also, the symptoms and behaviors of people suffering from EDNOS are similar to those that are suffering from anorexia and bulimia. People with EDNOS can face the same dangerous risk as people with anorexia and bulimia. 
As EDNOS was initially thought to be rare, and as 5 of the 6 proposed DSM-5 EDNOS presentations are well-defined, it seems likely that the "residual" (undefined) presentation accounts for most of the 40% of eating disorder cases diagnosed as EDNOS. Research is required into how many of these "residual" EDNOS diagnoses were eventually replaced by that of a recognised medical condition, whether psychologically or organically caused. While all organic causes should be ruled out prior to making a diagnosis of an eating disorder, in practice this is difficult as many physical conditions can also result in low weight, and may develop over time.
Rather than providing specific diagnostic criteria for EDNOS, DSM-IV lists six non-exhaustive example presentations, including individuals who:
- Meet all criteria for anorexia nervosa except have regular menstrual cycles
- Meet all criteria for anorexia nervosa except their weight falls within the normal range
- Meet all criteria for bulimia nervosa except they engage in binge eating or purging behaviors less than twice per week or for fewer than three months
- Purge after eating small amounts of food while retaining a normal body weight
- Repeatedly chew and spit out large amounts of food without swallowing
- Meet criteria for binge eating disorder
Although EDNOS (formerly called “atypical eating disorder”) was originally introduced in DSM-III to capture unusual cases, it is now the most commonly diagnosed eating disorder. Specifically, EDNOS accounts for approximately 40% to 60% of cases in eating disorder specialty clinics, and up to 90% of eating disorder diagnoses conferred in non-specialty psychiatric settings. The lifetime prevalence of EDNOS in the National Comorbidity Survey Replication, a large epidemiological study that interviewed a nationally representative sample of U.S. residents, was 4.64% among adults and 4.78% among adolescents. In addition, in a study based on a questionnaire regarding eating disorders sampled Norway's general female population and found that EDNOS had a lifetime prevalence of 3.0%. EDNOS is an especially prevalent category in populations that have received inadequate research attention such as young children, males, ethnic minorities, and non-Western groups.
Presentation and course
Despite its subclinical status in DSM-IV, available data suggest that EDNOS is no less severe than the officially recognized DSM-IV eating disorders. In a comprehensive meta-analysis of 125 studies, individuals with EDNOS exhibited similar levels of eating pathology and general psychopathology to those with anorexia nervosa and binge eating disorder, and similar levels of physical health problems as those with anorexia nervosa. Although individuals with bulimia nervosa scored significantly higher than those with EDNOS on measures of eating pathology and general psychopathology, EDNOS exhibited more physical health problems than bulimia nervosa.
Importantly, an EDNOS diagnosis may presage future diagnostic crossover into officially recognized eating disorder categories. For example, 40% of individuals with EDNOS go on to develop anorexia nervosa or bulimia nervosa within one to two years.
The many health problems associated with EDNOS are varied due to the heterogeneous nature of the diagnosis, are both psychological and physical, and vary greatly in severity. They include:
- Cardiac dysrhythmias
- Pseudo Bartter syndrome
- Oral problems - cheilosis, gingivitis, sialadenosis, etc.
- Hypoglycemia
- Iron Deficiency Anemia
Problems with the EDNOS diagnosis
|This section does not cite any references or sources. (April 2013)|
The preponderance of EDNOS in clinical practice poses many clinical and research challenges. Since EDNOS comprises so many heterogeneous presentations, no evidence-based treatment has been developed specifically for EDNOS, and geneticists have not been able to identify specific genes that confer EDNOS risk. Even though EDNOS is a serious eating disorder, health insurance companies may not provide coverage commensurate to that of anorexia or bulimia nervosa, and patients may find the diagnosis invalidating.
Changes made in the DSM-5
The DSM-5 Eating Disorders Work Group has made several revisions to the diagnostic criteria, which they hope will reduce the reliance on EDNOS in clinical settings, and promote treatment-seeking and research among affected individuals. The DSM-5, published in May of 2013, expands the diagnostic criteria for anorexia nervosa and bulimia nervosa, and elevates binge eating disorder to a formally recognized diagnosis. Furthermore, DSM-5 renames the EDNOS category Feeding or Eating Disorder Not Elsewhere Classified (FEDNEC), and provides the following named descriptions of example presentations:
- Atypical Anorexia Nervosa in which all criteria for anorexia nervosa are met except that the individual’s weight is within or above the normal range
- Subthreshold Bulimia Nervosa (low frequency or limited duration) in which all criteria for bulimia nervosa are met except the binge eating and compensatory behaviors occur on average less than once a week and for less than 3 months
- Subthreshold Binge Eating Disorder (low frequency or limited duration) in which all criteria for binge eating disorder are met, except the binge eating occurs on average less than once a week and for less than 3 months
- Purging Disorder (PD) in which patients purge without binging; they consume a normal amount of food and typically maintain normal weight
- Night Eating Syndrome (NES) in which patients have nocturnal eating episodes, or eat a large proportion of their daily calorie intake after dinner
- Other Feeding or Eating Condition Not Elsewhere Classified which is a residual category for all other cases that are clinically significant but do not meet the criteria for formal eating disorder diagnoses 
- Christopher G. Fairburn and Kristin Bohn (June 2005). "Eating disorder NOS (EDNOS): an example of the troublesome "not otherwise specified" (NOS) category in DSM-IV". Behaviour Research and Therapy 43 (6): 691–701. doi:10.1016/j.brat.2004.06.011. PMC 2785872. PMID 15890163.
- Fairburn, Christopher G.; Bohn, Kristin (2005). "Eating disorder NOS (EDNOS): An example of the troublesome "not otherwise specified" (NOS) category in DSM-IV". Behaviour Research and Therapy 43 (6): 691–701. doi:10.1016/j.brat.2004.06.011. PMC 2785872. PMID 15890163.
- "Eating Disorder Not Otherwise Specified (EDNOS)".
- American Psychiatric Association (2000). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association.[page needed]
- American Psychiatric Association (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). Washington, DC: American Psychiatric Association.[page needed]
- Button, Eric J.; Benson, Elizabeth; Nollett, Nollett; Palmer, Robert L. (2005). "Don't forget EDNOS (eating disorder not otherwise specified): Patterns of service use in an eating disorders service". Psychiatric Bulletin 29 (4): 134–6. doi:10.1192/pb.29.4.134.
- Fairburn, Christopher G.; Cooper, Zafra; Bohn, Kristin; O’Connor, Marianne E.; Doll, Helen A.; Palmer, Robert L. (2007). "The severity and status of eating disorder NOS: Implications for DSM-V". Behaviour Research and Therapy 45 (8): 1705–15. doi:10.1016/j.brat.2007.01.010. PMC 2706994. PMID 17374360.
- Martin, Corby K.; Williamson, Donald A.; Thaw, Jean M. (2000). "Criterion validity of the multiaxial assessment of eating disorders symptoms". International Journal of Eating Disorders 28 (3): 303–10. doi:10.1002/1098-108X(200011)28:3<303::AID-EAT7>3.0.CO;2-I. PMID 10942916.
- Nollett, C. L.; Button, E. J. (2005). "Questionnaire measures of psychopathology in eating disorders: Comparisons between clinical groups". European Eating Disorders Review 13 (3): 211–5. doi:10.1002/erv.632.
- Turner, Hannah; Bryant-Waugh, Rachel (2004). "Eating disorder not otherwise specified(EDNOS): Profiles of clients presenting at a community eating disorder service". European Eating Disorders Review 12: 18–26. doi:10.1002/erv.552.
- Zimmerman, Mark; Francione-Witt, Caren; Chelminski, Iwona; Young, Diane; Tortolani, Christina (2008). "Problems Applying the DSM-IV Eating Disorders Diagnostic Criteria in a General Psychiatric Outpatient Practice". The Journal of Clinical Psychiatry 69 (3): 381–4. doi:10.4088/JCP.v69n0306. PMID 18348598.
- Le Grange, Daniel; Swanson, Sonja A.; Crow, Scott J.; Merikangas, Kathleen R. (2012). "Eating disorder not otherwise specified presentation in the US population". International Journal of Eating Disorders 45 (5): 711–8. doi:10.1002/eat.22006. PMID 22407912.
- Götestam, K. Gunnar; Agras, W. Stewart. "General population-based epidemiological study of eating disorders in Norway". International Journal of Eating Disorders 18 (2): 119-126. doi:10.1002/1098-108X(199509)18:2<119::AID-EAT2260180203>3.0.CO;2-U. Retrieved 12 October 2014.
- Becker, Anne E.; Thomas, Jennifer J.; Pike, Kathleen M. (2009). Walsh, B. Timothy, ed. "Should non-fat-phobic anorexia nervosa be included in DSM-V?". International Journal of Eating Disorders 42 (7): 620–35. doi:10.1002/eat.20727. PMID 19655370.
- Thomas, J. J.; Crosby, R. D.; Wonderlich, S. A.; Striegel-Moore, R. H.; Becker, A. E. (2010). "A latent profile analysis of the typology of bulimic symptoms in an indigenous Pacific population: Evidence of cross-cultural variation in phenomenology". Psychological Medicine 41 (1): 195–206. doi:10.1017/S0033291710000255. PMID 20346191.
- Thomas, Jennifer J.; Vartanian, Lenny R.; Brownell, Kelly D. (2009). "The relationship between eating disorder not otherwise specified (EDNOS) and officially recognized eating disorders: Meta-analysis and implications for DSM". Psychological Bulletin 135 (3): 407–33. doi:10.1037/a0015326. PMC 2847852. PMID 19379023.
- Milos, Gabriella; Spindler, Anja; Schnyder, Ulrich; Fairburn, Christopher G. (2005). "Instability of eating disorder diagnoses: Prospective study". The British Journal of Psychiatry 187 (6): 573–8. doi:10.1192/bjp.187.6.573. PMC 2710504. PMID 16319411.
- Herzog, David B.; Hopkins, Julie D.; Burns, Craig D. (1993). "A follow-up study of 33 subdiagnostic eating disordered women". International Journal of Eating Disorders 14 (3): 261–7. doi:10.1002/1098-108X(199311)14:3<261::AID-EAT2260140304>3.0.CO;2-N. PMID 8275062.
- "Osteoporosis in women with eating disorders: comparison of physical parameters, exercise, and menstrual status with SPA and DPA evaluation." 31 (3). March 1990. pp. 325–31. PMID 2308003.
- Turner, Hannah; Peveler, Robert (April 2005). "Eating disorders and type 1 diabetes mellitus". Psychiatry 4 (4): 30–33. doi:10.1383/psyt.22.214.171.124442.
- American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA, American Psychiatric Association, 2013. Web. [access date: 18 October 2014]. dsm.psychiatryonline.org