OSFED: The 'Other' Eating Disorder

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Other Specified Feeding or Eating Disorder or OSFED, the eating disorder formerly known as EDNOS (Eating Disorder Not Otherwise Specified) is less well known than anorexia nervosa, bulimia nervosa, and binge eating disorder. However, it is actually the most common, representing an estimated 32 percent to 53 percent of all individuals with eating disorders. 

One problem with psychiatric diagnoses, in general, is that so many patients do not fit neatly into the typical diagnostic categories.

It’s not always clear-cut. Sometimes people meet most but not all of the criteria for a diagnosis.  In the case of eating disorders, a person who does not qualify for a specific diagnosis would be classified as OSFED. The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) includes 5 examples of patients who would be classified as OSFED:

1.  Atypical Anorexia Nervosa: This would include people who meet many but not all of the criteria for anorexia nervosa. For example, they may restrict food intake and display other features of anorexia nervosa without meeting the low weight criteria.
2.  Bulimia Nervosa of low frequency and/or limited duration: The individual may meet most of the criteria for bulimia nervosa, but the binge eating and/or purging occurs at a lower frequency and/or is of a limited duration.
3. Binge Eating Disorder of low frequency and/or limited duration: The individual meets the criteria for binge eating disorder but binge eating occurs at a lower frequency and/or is of a limited duration.

4. Purging Disorder: The individual engages in a purging of calories (by vomiting, misuse of laxatives or diuretics, and/or excessive exercising) aimed to influence weight or shape, but does not binge eat, which is the factor that distinguishes this disorder from bulimia nervosa. 
5. Night Eating Syndrome: The individual engages in recurrent episodes of night eating, eating after awakening from sleep, or engages in excessive food consumption after the evening meal.

There is awareness and recall of the eating.

The preceding are just examples; OSFED has many other manifestations. 

One misconception about OSFED is that it is less severe or subclinical.  This is not necessarily true, and it keeps many people who are suffering from seeking help. In a study by Fairburn and colleagues in 2007 of EDNOS (OSFED was previously known as ‘eating disorder not otherwise specified’), the researchers found that most cases of EDNOS were "mixed" in character and not subthreshold forms of anorexia nervosa or bulimia nervosa:  “the clinical features of anorexia nervosa and bulimia nervosa are present but combined in subtly different ways to those seen in the two currently specified syndromes.”

While some of the people who are diagnosed with OSFED may have less severe diagnoses, many of the people with OSFED have as severe an eating disorder as those who meet criteria for anorexia nervosa, bulimia nervosa, and binge eating disorder. Fairburn and colleagues noted that “eating disorder NOS is common, severe and persistent.” Individuals with OSFED will experience health risks similar to those of the other eating disorders.

 At least one previous study showed the mortality rate for EDNOS was as high as for individuals who meet the thresholds for anorexia.

Furthermore, since eating disorder diagnoses are not stable over time it is also not uncommon for people to meet the diagnosis of OSFED on their way to a full-blown diagnosis of anorexia, bulimia, or binge eating disorder, or on their way to recovery.  In another study of EDNOS, Agras and colleagues concluded, “EDNOS is a way-station for those moving from a full ED or from remission to another ED.”

Remember, there is not always a firm line between disorder and health and there are several shades of gray in the middle. Research supports that early intervention makes a big difference in recovery.  Cognitive Behavioral Therapy (CBT or CBT-E) is one of the most successful treatments for bulimia nervosa and binge eating disorder and has also been successfully applied to individuals with OSFED, especially individuals who have OSFED with symptom profiles similar to these disorders. 

Even if your experience does not seem to fit a diagnosis, if you are experiencing distress related to eating, exercise, shape, and weight, you should consult a professional. 

Sources:

Agras et al. A 4-year prospective study of Eating Disorder NOS compared with full eating disorder syndromes. International Journal of  Eating Disorders. 2009.

Crow S et al. Increased Mortality in Bulimia Nervosa and Other Eating Disorders. The American Journal of Psychiatry. 2009.

Fairburn et al. The severity and status of eating disorder NOS: Implications for DSM-V. Behaviour Research and Therapy. 2007. 

Keel P, Brown T, Holm-Denoma J, Bodell LP. Comparison of DSM-IV versus proposed DSM-5 diagnostic criteria for eating disorders: reduction of eating disorder not otherwise specified and validity. International Journal of Eating Disorders. 2011.

Ornstein et al. Distribution of eating disorders in children and adolescents using the proposed DSM-5 criteria for feeding and eating disorders. Journal of Adolescent Health. 2013. 

Thomas J, Vartanian L, Brownell K. The relationship between eating disorder not otherwise specified (EDNOS) and officially recognized eating disorders: meta-analysis and implications for DSM. Psychological Bulletin. 2009.

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