What Is Atypical Anorexia Nervosa?

Source: Photo by Cristian Newman on Unsplash

"You aren’t thin enough to have an eating disorder."

If you have struggled with an eating disorder and live in a larger body, you have likely heard some version of this. Perhaps you bravely disclosed your restrictive eating at your physician’s office, only to be placed on the scale and told: “Your weight looks okay, I wouldn’t worry about it too much.” Or your family and friends responded to your dramatic weight loss with praise and congratulations instead of concern. “You look fabulous, whatever you are doing, keep it up!” In our weight-biased culture, when a fat person loses weight, it is almost always seen as a good thing. Even when that weight loss is caused by an eating disorder.

Eating disorders in people at higher weights are commonly misdiagnosed, leading to delayed treatment and more dire prognoses. Sometimes it is not until the eating disorder has progressed to the point that the person becomes underweight that they are finally able to get the treatment they so desperately need. Many doctors view an eating disorder in someone at a higher weight as less serious than an eating disorder in someone who is underweight. But is this true? Are eating disorders less serious in people at higher weights?

A research study by Sawyer et al. (2016) examined adolescents with atypical anorexia nervosa (AN) and compared them to adolescents with full-threshold AN to assess how the physical and psychological complications of these two illnesses compare. Atypical anorexia nervosa is defined by the DSM-V as an eating disorder wherein “all of the criteria for AN are met, except that despite significant weight loss, the individual’s weight is within or above the normal range.”

Results of this study indicated that, when compared with full-threshold AN, adolescents diagnosed with atypical AN were more likely to experience more severe eating disorder symptoms, lower self-esteem, and present for treatment having lost more weight over a longer period of time. Medical complications of atypical AN and full-threshold AN were similar; no significant differences were found on resting pulse rate, frequency of bradycardia, marked orthostatic changes, hypothermia, or requiring hospital admission. There were also no significant differences on measures of binge eating, purging, psychiatric comorbidity, use of psychotropic medications, self-harm, suicidal ideation, severity of depressive symptomology, or obsessive compulsiveness. Participants with atypical AN were more likely to have a history of meeting BMI criteria for “overweight” or “obese” and were less likely to experience amenorrhea (loss of menstruation).

This study concluded that atypical AN in adolescents is a major psychiatric illness with physical and psychological complications similar to full-threshold AN, except with more severe distress related to eating and body image. Despite not being underweight, nearly 1 in 4 adolescents in this study with atypical AN had bradycardia, 1 in 3 had amenorrhea, and more than 40% required inpatient hospitalization. Thirty-eight percent had a psychiatric comorbidity (depressive disorders were most common at 31% followed by anxiety disorders at 17% and obsessive-compulsive disorder at 5%) and 43% experienced self-harm or suicidal ideation.

We must look beyond body weight when diagnosing eating disorders. Weight loss should always be a red flag, especially in adolescents whose weight typically trends towards an upward trajectory. This does not mean that everyone who loses weight has an eating disorder. The fact is, we seldom know what is behind someone else’s weight loss; it could be a change in lifestyle, surgery, cancer, depression, grief, or an eating disorder. If you are a medical professional, it is your obligation to ask what is going on. Don’t assume that weight loss is healthy or intentional. It can be one of the most visible manifestations of underlying illness and suffering.

Alexis Conason is a clinical psychologist specializing in the treatment of psychological issues related to bariatric surgery, overeating disorders, body image dissatisfaction, and sexual issues. She is also the founder of The Anti-Diet Plan.