EDNOS or OSFED?
There are a number of Eating Disorder classifications, and if you're recently diagnosed, or supporting a loved one, or perhaps have been trying to find out more to understand what you've been going through, it can all be a little confusing. There are two acronyms in particular that seem to be commonly used quite interchangeably, which are, in fact, not quite the same thing.
Eating Disorder Not Otherwise Specified or EDNOS was a diagnosis from the DSM IV which was utilised for individuals who had eating disorder symptoms and significant distress, but did who not meet the full criteria for any of the other eating disorder diagnoses.
EDNOS used to be the most commonly diagnosed eating disorder and encompassed a varied group of people. Approximately 40-60% of cases in eating disorder treatment centres came under EDNOS diagnosis and about 75% of individuals with eating disorders seen at community settings had EDNOS. 
The Diagnostic & Statistical Manual (DSM-IV) currently lists six diagnostic examples of EDNOS.
All criteria for anorexia are met, however the individual’s weight falls within normal range (despite significant weight loss).
All criteria for anorexia are met, however the individual has regular menstrual cycles.
All criteria for bulimia are met, however purging or binge-eating episodes happen less than two times per week or for fewer than three months.
Someone purges after eating a small amount of food (e.g. self-induced vomiting after eating two biscuits) and has a normal body weight.
An individual repeatedly chews and spits large amounts of food.
All of the criteria are met for binge eating disorder. 
In The DSM-v, the diagnosis of EDNOS was formally changed to Other Specified Feeding or Eating Disorder or OSFED. 
OSFED hasn't received much media attention compared to Anorexia and Bulimia. The figures though, are alarming. It is thought to be the most common, with an estimated 32% to 53% of all individuals with Eating Disorders who have received OSFED as a diagnosis. 
According to The National Association of Anorexia Nervosa and Associated Disorders, the following are five subtypes of OSFED:
Atypical Anorexia Nervosa: An individual has restrictive behaviours and other symptoms of anorexia, however they do not meet the low weight criteria.
Bulimia Nervosa: An individual meets the criteria for bulimia but engages in bingeing or purging behaviours at a lower frequency and/or for a limited period of time.
Binge Eating Disorder: An individual meets the criteria for binge eating disorder but engages in bingeing behaviours at a lower frequency and/or for a limited period of time. A person experiences episodes of eating, in a short period of time an amount of food that is larger than what most individuals would consume and feels out of control.
Purging Disorder: Purging behaviours that may include vomiting, excessive exercise, laxatives, etc.
Night Eating Syndrome: Recurrent episodes of night eating. The person recalls what they have eaten. 
Risks Can Be Severe
Its quite a common belief that a diagnosis of OSFED is not that serious. This can be reinforced by the Eating Disorder symptom of anosognosia, (the symptom of severe mental illness that impairs the sufferer's ability to understand and perceive their illness) resulting in a failure to seek treatment or support; Some research has shown mortality rates of EDNOS, (now OSFED) are as high as those for individuals who meet the thresholds for Anorexia.
 Many studies have shown that individuals with this diagnosis experience eating pathology and medical consequences that are just as, if not more, severe than individuals who receive a formal anorexia or bulimia diagnosis. Furthermore, one recent study found that 75% of individuals with this diagnosis had co-occurring psychiatric disorders and 25% endorsed suicidality.
The risks associated with OSFED are worrying and are similar to those of the Eating Disorders the behaviours most closely resemble. They include:
Inflammation and rupture of the oesophagus and stomach from frequent vomiting
Chronic constipation or diarrhoea
Osteoporosis - a condition that leads to bones becoming fragile and easily fractured
Irregular or slow heart beat which can lead to an increased risk of heart failure
Loss of or disturbance of menstrual periods in girls and women
Increased risk of infertility in men and women
Treatment for OSFED
Full recovery from OSFED is possible. If you are struggling , it is crucial to reach out for help and support.
Due to the atypical nature of the illness, it is essential to have personalised support adapted to your individual symptoms and this is not possible from generic sources of advice.
Just remember, you don't need to keep suffering, and you can recover.
:A closer look at eating disorder not otherwise specified. The Centre for Eating Disorders at Shepard Pratt.
: American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders (4th Ed.) United States of America: American Psychiatric Association.
: Muhlheim, L. (2015). OFSED, The 'Other' Eating Disorder.
 The National Association of Anorexia Nervosa and Associated Disorders, other specified feeding or eating disorder. (2016)
A closer look at eating disorder not otherwise specified. The Centre for Eating Disorders at Shepard Pratt.