Eating disorder not otherwise specified (EDNOS) refers to a condition where a person may engage in a variety of behaviours and symptoms from across the spectrum of the specifically defined conditions, but may not fit comfortably into one of those classifications.
For example, a person may show all other symptoms and behaviours of anorexia, but without significant weight loss; or a person may show the symptoms of bulimia, but is not binging/purging as regularly as required by the strict diagnostic criteria. One of the most significant areas currently included within the 'EDNOS' category is Binge Eating Disorder.
EDNOS is thought to account for up to 50% of diagnoses of eating disorders, however because of the difficulties around the diagnostic criteria it is not recognized to the same extent.
While a less concrete diagnosis can be difficult, because the same behaviours are involved the same health risks exist as in the case of other eating disorders.
As such it is important to acknowledge the disorder, seek support, and address any physical/medical side-effects as well as addressing the emotional background to the behaviours.
In 2013, Other Specified Feeding or Eating Disorder (OSFED) replaced the eating disorder category previously described as EDNOS.
OSFED may apply to individuals who do not meet the full criteria for anorexia, bulimia or binge eating disorder. They may experience clinically significant symptoms that are problematic and distressing in how they manage their relationship with food. This may include disordered eating similar to other eating disorders or eating behaviours that are associated with distress, impairment and risk of pain, death or disability.
It is important to stress that OSFED is no less serious of an issue than other eating disorders. Individuals affected by OSFED may present with emotional distress and impairment compared with those who do not have an eating disorder. Consequently, they may require ongoing support and treatment to manage their difficulties.
Subtypes of OSFED include:
Atypical anorexia nervosa: A person develops all of the criteria for anorexia, except that, despite significant weight loss, a person may be within or above the normal weight range.
Bulimia nervosa of low frequency/limited duration – A person may meet the criteria for bulimia, though binge eating or compensatory behaviours may occur, on average, less than once a week and/or for less than 3 months.
Binge eating disorder of low frequency/limited duration - A person may meet the criteria for binge eating disorder, though binge eating occurs, on average, less than once a week and/or for less than 3 months.
Purging disorder: A person may use purging behaviours to change their weight or shape, in the absence of binge eating.
Night eating syndrome: A person may experience recurrent episodes of night eating. This may occur following excessive consumption of food following an evening meal. The night time eating is not explained by external factors (medication, sleep cycle, other medical disorders) in a person’s life and may cause significant distress and impairment in functioning.
 American Psychiatric Association (2013) Desk Reference to the Diagnostic Criteria for DSM-5. American Psychiatric Association.