Examining Atypical Anorexia Nervosa And Its Diagnosis

Psychiatric illnesses are complex and varied. Their diagnoses are very specific; certain criteria that may seem similar to non-professionals can make the difference between, for example, obsessive-compulsive disorder and general anxiety. Because of the specificity of mental health diagnoses the American Psychiatric Association (APA) created a diagnostic manual to help outline these disorders for professionals and assist in making their diagnoses more accurate. The first Diagnostic and Statistical Manual of Mental Disorders was issued in 1952.

Since then, The DSM has gone through several editions. The current one, published in 2013, made some changes to the way eating disorders were specified and diagnosed. Perhaps the most important one was to include binge eating disorder, the most common form of eating disorder in the United States, as a standalone diagnosis. However, later revisions have worked on making a diagnosis of some less common and less-known eating disorders.

From OSFED to a Sharper Focus

The latest edition of the DSM (the fifth, published in 2013) made some major changes to how eating disorders are diagnosed. Binge eating disorder was designated a standalone form of eating disorder to reflect its unique symptoms and frequent occurrence. However, other eating disorders were also redesignated.

In earlier editions, many less-common eating disorders or variations of established disorders like anorexia nervosa and bulimia nervosa were lumped into a catchall category known as OSFED (other specified feeding or eating disorder).This category simply means that a person displays some symptoms of another eating disorder without meeting all the diagnostic criteria. For example, a person who binges and purges without experiencing body dysmorphia (distorted body image) may not qualify for a diagnosis of bulimia nervosa, and would instead be diagnosed with OSFED.

One drawback of this approach to diagnosis is that some people consider OSFED diagnoses as somehow less dangerous. Almost everyone is aware of the dangers of a disorder like anorexia nervosa, but they figure that if the person doesn’t receive a diagnosis of it for whatever reason, it’s “not as bad.” However, if a person doesn’t meet the criteria for a specific eating disorder, their disordered behaviors can still be harmful. This leads us to “atypical” anorexia nervosa.

First, What Is Anorexia Nervosa?

Anorexia nervosa is defined by the DSM-5 as disordered eating that involves restricting caloric intake, sometimes to extreme lengths. Individuals with this disorder also experience distorted body image, thinking they are overweight no matter how underweight they become. The typical stereotype of someone with anorexia nervosa is that of a person who is thin, ill, and malnourished. Anorexia is perhaps the most well-known eating disorder among the general public; almost everyone has heard of a friend or even a celebrity who has struggled with it.

In recent years, the treatment of anorexia nervosa has grown by leaps and bounds. Although it remains a serious disorder that can lead to serious (and sometimes fatal) health risks, positive outcomes have become more likely with the advent of specialized eating disorder treatment on residential, outpatient, and virtual platforms. Most physicians and virtually every mental health professional is equipped to diagnose and begin treatment for this disorder.

What Makes Some Forms of Anorexia Nervosa “Atypical”?

However, there is evidence of another type of anorexia nervosa that primarily concerns adolescents who have lost a significant amount of weight but are not considered clinically underweight. Although atypical anorexia nervosa is indeed an eating disorder, teens in anorexia nervosa recovery often do not show outward signs of serious medical complications associated with other eating disorders. Consequently, anorexia nervosa treatment centers may perform blood and urine tests to determine if underlying health problems need to be addressed before beginning psychological therapy.

Atypical anorexia nervosa (AAN) is also an Other Specified Feeding or Eating Disorder (OSFED). The DSM-V lists AAN, bulimia nervosa of limited duration/low frequency, binge eating disorder of limited duration and/or low frequency, purging disorder, and night eating syndrome as Other Specified Feeding or Eating Disorders as well.Although these syndromes may not be standalone disorders as per the DSM-5, they are all serious and require specialized treatment. An “atypical” tag notwithstanding, each of these is a serious condition.

Symptoms of Atypical Anorexia Nervosa

The Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders defines atypical anorexia nervosa (AAN) as an eating disorder that meets all criteria for anorexia nervosa except that the individual does not reach a point where they are considered medically underweight. People with AAN do not always lose weight, but generally speaking, the weight loss is noticeable. Some cases may not become underweight due to quirks of their metabolism, others may cycle through periods of binging or ceasing restriction, and yet others may start restricting when they are overweight, thus losing weight without becoming medically deemed so.

In addition, people with AAN present the same symptoms of cognitive distortions and abnormal behaviors characteristic of anorexia nervosa such as depression, anxiety, increased risk of self-harm, and significant weight loss. Physical complications experienced with AAN are similar to complications diagnosed in anorexia nervosa patients, other than becoming underweight. In some cases, people with atypical anorexia nervosa may even be above their normal weight range.

People with anorexia nervosa often deny they have an eating disorder or go to great lengths to hide their behaviors. Secrecy about eating and discomfort at meals are common. If confronted with their eating disorder, people with AAN may try to minimize the impact of their eating disorder on their health, criticize family and friends for “picking” on them, or try to deflect the situation by changing the topic or assigning blame to their current stressors (i.e. relationship, job stress).

For those closest to someone with AAN, it can seem hard to start a conversation about the possibility that they need professional help. It’s best to focus n concerns about their health, but without any semblance of judgment about their behaviors. Asking a therapist or doctor to help is recommended; some eating disorder treatment programs can help schedule an intervention. Most insurance plans have some form of coverage for eating disorder treatment, but it’s best to check before committing to any course of action – telling someone they are going to treatment and then reneging is counterproductive.

Eating Disorder Treatment Professionals Can Treat Atypical Anorexia Nervosa

People with AAN and their loved ones such as family, friends, and partners often do not realize they have a serious eating disorder because of the misconceptions about what an eating disorder “looks like”. Because they are not extremely thin, they may not think they are sick enough to suffer from an eating disorder. Unfortunately, being uninformed about AAN can prevent those loved ones from seeking out help.

Weight loss is not the defining criterion for AAN and symptoms of anorexia nervosa are not the same as symptoms of AAN. However, there is much overlap between the two eating disorders, and every effort to correct the behavior should be taken when receiving a diagnosis for any kind of eating disorder.

Anorexia nervosa treatment centers specialize in diagnosing all eating disorders, including AAN, bulimia nervosa, binge eating disorder, and nighttime eating disorder. If a person is engaging in behaviors involving food restriction, counting calories, counting fat grams, or performing ritualistic food activities during meals but is not underweight, they should be evaluated by professionals trained to recognize symptoms of an eating disorder.


With 20 years of behavioral health business development experience, Carrie combines world-class marketing, media, public relations, outreach and business development with a deep understanding of client care and treatment. Her contributions to the world of behavioral health business development – and particularly eating disorder treatment – go beyond simple marketing; she has actively developed leaders for her organizations and for the industry at large.