Anorexia and bulimia are probably the most familiar types of eating disorders, but they are not the most common. Some 50 to 60 percent of patients don't quite make the cut to be diagnosed with full-blown anorexia or bulimia, and are instead classified as having an eating disorder "not otherwise specified" (EDNOS).
But this group is so vast, and the cases within it so diverse, that many in the field believe it creates more problems than it does solutions in terms of treating patients and understanding the syndromes. Patients lumped into this unspecified group can also have misperceptions about their condition, thinking it is not as serious as anorexia or bulimia. But in fact, recent studies have found that there really isn't a medical difference between the three recognized types of eating disorders.
Now, physicians and psychiatrists are taking action to remedy the situation. They are proposing revisions to the psychiatric "bible," the Diagnostic and Statistical Manual of Mental Disorders, or DSM, for the newest version (DSM-5) to be published in 2013. The suggested changes include relaxing the strict criteria for anorexia and bulimia somewhat, and giving other conditions, such as binge eating, their own official labels.
These more specific labels could be a boon to treatment and the mental health of the patient, who will finally know what he or she "has." In addition, experience has shown that when a disorder gets a name, more research and attention is paid to it. Even so, some experts aren't sold, saying these DSM changes won't make any real difference as far as treatment goes.
"At the moment it's like a housekeeping job, we're just trying to make it tidy," said Chris Fairburn, a professor of psychiatry at the University of Oxford in England. "And that’s good in the sense of nicely sort of putting people into different drawers if you like…it's tidy, but it may be meaningless."
Regardless of the changes made, the most important thing is for doctors not to make decisions arbitrarily, but to revise the diagnoses based on what they know from scientific research, said Dr. Rebecka Peebles, an instructor of pediatrics at Stanford University School of Medicine who has studied pediatric eating disorders.
"Currently the diagnostic criteria for anorexia and bulimia have not been decided based on evidence; they've been decided based on expert consensus," Peebles said. "And that is valuable, I don’t discount that at all … but I think now that we are starting to have more evidence, we should consider using that evidence to really reshape these criteria," she said.
Every psychiatric disorder has a "not otherwise specified" group, which is "designed as a sort of a catchall residual category for people who don't have the formal diagnosis, yet clearly have the psychiatric disorder," Fairburn said.
That means those with EDNOS have not met the criteria for either anorexia or bulimia, which are quite rigid. Currently, someone is considered anorexic if they have a significant fear of gaining weight, are at less than 85 percent of their expected body weight, and have missed three or more consecutive periods, if they are a girl and old enough to menstruate.
Someone is diagnosed with bulimia if they have had episodes of binge eating at least two times a week for three or more months, followed by some type of behavior to make up for the binge, such as vomiting, that also occurs two or more times per week for three or more months.
Some patients just miss the mark for anorexia because they have not lost their period, or for bulimia because they do not binge and purge frequently enough. Other cases are a bit more complex. For instance, children might be diagnosed with EDNOS because they are not able to verbalize the same concerns about their weight that older adolescents can, Peebles said. Or it can be someone who only binges or only purges, or someone who fears gaining weight, but isn't underweight. The list goes on.
For any given psychiatric disorder, usually only about 5 percent of patients are lumped into the "not otherwise specified group," as opposed to the more than 50 percent lumped into that group for eating disorders, according to Fairburn.
Its large size and miscellaneous nature make EDNOS a problem on a number of fronts.
"It limits the information that the term communicates, and it limits clinical knowledge about how folks with the diagnosis should be treated, and it limits research about how to get that knowledge," said Dr. B. Timothy Walsh, a psychiatry professor at Columbia University, and the chair of the Eating Disorders Workgroup for DSM-5, a committee that will review information and make recommendations for changes to the DSM.
"So it’s a problem on a bunch of spheres," he said.
There are also no clear treatment guidelines for EDNOS. There can't be, because cases within the category can range from someone who is almost anorexia and underweight, to someone who is overweight due to binge eating.
Additionally, the patients themselves might have a skewed view of their condition if it doesn't have an official label.
"Sometimes patients who are diagnosed with EDNOS don't really understand the seriousness of their illness, because they tend to minimize it, thinking, 'Oh I don't meet [the] full criteria for [an] eating disorder, it must not really be that bad,'" said Jennifer J. Thomas, an instructor in psychology at Harvard Medical School.
This can lead to people waiting longer to seek treatment. "Or once they're in treatment, they won't feel as strong of a need to work towards recovery as someone who has a full diagnosis," Thomas said.
Parents of children with eating disorders can also suffer from these misperceptions, Peebles said. Sometimes, when parents find out their child does not have the full threshold anorexia or bulimia, "they feel relieved and they feel like, 'OK we've got some time here,'" Peebles said. However, a recent study by Peebles found that EDNOS conditions do indeed present real, medical risks.
It can also be difficult for EDNOS patients to receive insurance coverage for a treatment if the insurance company only recognizes anorexia and bulimia as eating disorders, Thomas said.
Several recent studies have found cases of EDNOS are close to or just as dire as full-blown anorexia or bulimia.
In one, Peebles and her colleagues collected health data from more than 1,300 females ages 8 through 19 with eating disorders. The researchers quantified how medically severe the patients' conditions were with measurements of heart rate, blood pressure, body temperature, and levels of electrolytes, including potassium and phosphorus.
About 60 percent of EDNOS patients qualified as needing hospitalization. As a group, the not-specified patients weren't as "sick" as those with anorexia, but were generally worse than those with bulimia.
"I don’t mean to say that bulimia was not severe, but EDNOS was, as a group, more severe," Peebles said.
The researchers also broke down EDNOS into subcategories, including partial anorexia and partial bulimia — patients whose conditions were just shy of meeting criteria for anorexia or bulimia.
"Partial anorexia and partial bulimia, even though currently they're both wrapped in the EDNOS umbrella, were each more similar to the full threshold illness than they were to each other," Peebles said. The results were published in the May issue of the journal Pediatrics.
Psychologically, EDNOS and the labeled eating disorders are also similar.
Last year, Thomas and her colleagues reviewed 125 studies on eating disorders published over the last 20 years. They looked at how severe the conditions were in terms of both a psychological problems and health problems.
"Overall, it looks like people with EDNOS have a disorder that's really just as severe as people with anorexia and bulimia; it's just that they don't meet the full criteria," Thomas said. "So, it isn’t the case that it’s a milder disorder that we should worry less about or [is] any less in need of treatment," she said.
Thomas' study was published in May 2009 in the journal Psychological Bulletin.
To shrink the EDNOS group, experts have proposed to expand the anorexia and bulimia diagnoses. For instance, the "missed periods" requirement could be taken out of the anorexia diagnosis, along with the exact weight requirement. And for bulimia, the binging and purging frequency could be decreased to once a week.
Also, binge eating disorder could be made an official eating disorder, taking it out from under the EDNOS umbrella.
While the changes are not yet set in stone, some are skeptical that they will work. Fairburn, of the University of Oxford, applied these criteria to a large database of eating disorder patients, and found that the proposed changes would reduce the number of EDNOS diagnoses from about 50 percent to 25 percent.
"So, this helps...but it doesn't solve the problem," Fairburn said. Those leftovers are mixed cases, having features of both anorexia and bulimia.
Fairburn says it is important not to lose sight of the reason why diagnoses are made — mainly to help clinicians treat patients. So it might be that making more categories for eating disorders is not the answer.
One study by Fairburn and his colleagues, published last year in the American Journal of Psychiatry, found that EDNOS and bulimia patients respond similarly to treatment. "If that's true, then there's no need to make a distinction, we can just lump them both together," he said.
History also shows that giving disorders a name does have its benefits.
"One thing I've seen…just looking at the literature in the past 20 years, is that as soon as a syndrome gets a name and a definition, researchers will start to research it, and clinicians will start to treat it," Thomas said.
For instance, the term "binge eating disorder"' was introduced back in 1959, but it wasn't until it was described in the appendix of the DSM IV (published in 1994) that people began to study it in a detailed way and look at how to treat it, according to Pamela Keel, a psychologist at Florida State University who studies eating disorders.
The next version of the DSM could include short descriptions of disorders within EDNOS, Walsh said, such as purging disorder (a condition in which patients purge but don't binge.) The hope is that a name would advance understanding about these conditions, just as it did for binge eating disorder, Walsh said.
"So even if they are in a not elsewhere classified…they nonetheless can be identified with a name, so that doctors can communicate better about them, and we can collect information about them," he said.