Six month of blogging and I have yet to do a proper post on the prevalence of eating disorders. I think it is about time. I see all sorts of numbers thrown around, often depending on the purpose of the article and the author’s bias. Is it 1 in 1000, 1 in 100, 1 in 20 or maybe even 1 in 2? Who is right?
Well, it is a tricky question to answer.
The number depends on how the particular study was conducted. Here are some factors that may influence the final rates: the population being studied, the sample size" data-definition="explanatory-dictionary-definition-364"sample size, the definition of eating disorder, the methods used by researchers to identify and screen for individuals with eating disorders, the number of years over which data is collected, and so on. In other words, a lot! That’s why in order to get a better sense of the true numbers, I prefer to look at review articles summarizing several years worth of epidemiological studies.
For this post, I picked a relatively recent review, published in May …
Eating disorder not otherwise specified (EDNOS), the catch-all diagnosis for eating disorder patients that don’t neatly fit into the DSM-IV anorexia nervosa (AN) or bulimia nervosa (BN) categories, is often thought to be less severe. Patients with sub-threshold AN or BN (missing one or two criteria) fall into the EDNOS (a large proportion, perhaps the majority, of patients). The inherent assumption in the word sub-threshold is that the patient is not as sick. Symptom frequency and behaviours are not that bad.
Increasingly, research is showing otherwise (which comes as no surprise for those of us who have struggled with eating disorders).
One study that has illustrated this quite nicely was published in 2009 by Dr. Scott Crow and colleagues in the American Journal of Psychiatry (freely available online here). Given that most ED mortality research has focused on anorexia nervosa, Crow et al wanted to compare mortality (from all-causes and suicide specifically) in patients with anorexia nervosa as well as bulimia nervosa and EDNOS. Furthermore, they were interested in studying a heterogenous sample over an extended period, …
You often hear that anorexia nervosa has the highest mortality rate of any psychiatric illness, but you might struggle to find the rates for bulimia nervosa or EDNOS. Even for AN, the most common cause of death is rarely reported and the reported rates often vary a lot (depending on the study (and the media outlet).
I wanted to find out what are: (1) the mortality rates in BN and EDNOS and (2) the common causes of death in these disorders. A relatively recent meta-analysis (click here for some background, pros and cons of meta-analyses) of 36 studies, which addressed some of my questions, was published by Arcelus and colleagues.
They excluded studies that had less than 15 patients and/or <1-year follow-up.
So, what did they find?
Mortality in Anorexia Nervosa: