Psychiatric diagnosis is a tricky business. I am reminded of this often when I ask people questions about their psychiatric history or current symptoms. For people with eating disorder symptoms, it can be overwhelming to figure out what category they fit into and who to reach out to for help.
In the feeding and eating disorders section of the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (or DSM-5), there are six different feeding and eating disorder categories. There are also five Other Specified Feeding and Eating Disorders. Among the eating disorders, two commonly get confused – anorexia nervosa, binge-purge subtype, and bulimia nervosa.
To better understand the differences between the two, it is helpful to turn first to the DSM-5.
Defining the Disorders
The hallmark features of anorexia nervosa:
- restrictive eating resulting in an abnormally low weight for adults or a failure for kids and teens to grow as they should
- fear of weight gain or becoming fat (or an inability to eat in a way that supports a healthy weight)
- body image distortion or relying heavily on body weight in self-evaluation, and
- difficulty recognizing the seriousness of not eating enough for their body’s needs.
Approximately half of adults with anorexia nervosa have the restricting-only variant. The other half meet criteria for the binge-purge subtype. This involves recurrent binge eating and/or purging. Purging refers to inappropriate behaviors that aim to compensate for food consumed. This includes self-induced vomiting or misuse of medicines like laxatives, diuretics, or enemas.
Like those with the binge-purge subtype of anorexia nervosa, people with bulimia nervosa experience regular binge eating and purging (at least once weekly). However, those with bulimia nervosa:
- experience both binge eating episodes and purging behavior, not one or the other, and,
- have weights within or above a normal range.
Like those with anorexia nervosa, people with bulimia nervosa tend to eat restrictively (outside of binge episodes). They are also very concerned with their body weight and shape. Sometimes, these aspects of appearance are a major factor in how people with these disorders evaluate themselves. Severe dissatisfaction is common, but tends to be distinct from that experienced by individuals with body dysmorphic disorder.
Diagnostic Crossover
Part of the confusion between these diagnoses is historical. Before the publication of the DSM-IV in 1994, people could be diagnosed as having both anorexia and bulimia nervosa at the same time. It wasn’t until 1994 that the American Psychiatric Association noted the differences between the two disorders, and separated anorexia nervosa into its two subtypes. While individuals are now diagnosed as either having anorexia nervosa binge-purge subtype or bulimia nervosa, it is possible to move from one diagnostic category to the other, based on weight changes.
In research looking at the diagnostic crossover in an adult, female sample over 7 years, 54% of individuals with an intake diagnosis of anorexia nervosa binge-purge subtype crossed over to bulimia nervosa. Approximately half of this group crossed over in the course of progressing to partial or full eating disorders recovery (a good reminder that recovery is possible!). The other half who experienced crossover to bulimia nervosa were likely to cross back into anorexia nervosa. A smaller proportion (14%) of people with an intake diagnosis of bulimia nervosa went on to meet criteria for anorexia nervosa. But all who crossed over did so to the binge-purge subtype.
Why Diagnosis Matters
The differences between the two eating disorders may not seem to be that big of a deal. Yet proper classification is useful to patients who are seeking treatment and to clinicians. Treatment for both disorders:
- targets eating patterns,
- breaking binge eating and/or purging behaviors, and
- improving body image.
The way this is accomplished will vary slightly. For example, those with anorexia nervosa will need to restore weight to maximize health. They will think carefully with their clinician about what level of care will help them accomplish this goal (and/or if a family-based approach might help). Those with bulimia nervosa may want to try psychotherapies shown to work for their disorder – cognitive behavioral therapy as a first-line treatment and interpersonal therapy as a second-line treatment – and/or medication.
If you or someone you know is experiencing symptoms of a feeding or eating disorder and is looking for treatment, read up on seeking mental health care (as well as common myths about treatment).
Also consider the following referral resources:
- Give us a call at 646-774-8066 or email us at edru@nyspi.columbia.edu
- National Eating Disorders Association– Contact this national US helpline for a list of specialized, eating disorder treatment resources.
- American Psychiatric Association– Find a psychiatrist to provide a comprehensive psychiatric evaluation, including medication recommendations.
- Association for Behavioral and Cognitive Therapies– Search for a cognitive behavioral therapist by location, specialty, and insurance.
- Psychology Today– Search by a variety of factors, like location, specialty, and insurance for an outpatient psychotherapist.
[…] eating and loss of control eating is a feature of several defined eating disorders, including bulimia nervosa, anorexia nervosa binge-purge subtype, and binge-eating disorder, and improving the regularity of one’s eating pattern – eating 3 […]
[…] be severe enough to rise to the level of a clinical eating disorder, such as anorexia nervosa and bulimia nervosa. However, disturbances in eating patterns may also be “sub-clinical.” This means that the […]