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Thoughts on DSM-V: Bulimia and BED

Posted Feb 23 2010 6:48pm
As I promised two days ago , here are my thoughts on the other changes made to the DSM. I blogged previously about my thoughts related to the changes made about anorexia nervosa, so now it's onto the other diagnoses.

Bulimia Nervosa

The changes to the BN diagnosis were twofold
  • the frequency of binge eating and purging was decreased from 2x/week for 3 months to 1x/week for three months

  • the "non-purging" BN subtype was eliminated, and merged with Binge Eating Disorder
The first criteria is pretty straightforward and there is quite a bit of evidence to indicate that so-called "sub-threshold" bulimia is just as severe as "threshold" bulimia in the DSM-IV ( Krug et al, 2008 ; Wilson and Sysko, 2009 ). This change isn't anything I have any desire to argue with.

The second criteria is more problematic. The drafters of the ED criteria for DSM-V had this rationale about the change
DSM-IV requires that sub-type (purging or non-purging) be specified. A literature review indicated that the non-purging subtype had received relatively little attention, and the available data suggested that individuals with this subtype more closely resemble individuals with Binge Eating Disorder. In addition, precisely how to define non-purging inappropriate behaviors (e.g., fasting or excessive exercise) is unclear.

Deletion of this subtype is recommended. This also requires rewording of Criterion B.
Criterion B specifies "inappropriate compensatory behaviors," and these behaviors would be limited to self-induced vomiting, and misuse of laxatives and/or diuretics. To some extent, I see the difficulties in defining fasting or excessive exercise- it isn't clear. But my next question would be then to define the "misuse" of laxatives and diuretics. So if you binge and then you can't take a crap and you swallow a few pills, is that misuse? What if the box says take two to four pills, and you always take four because you're convinced that any less wouldn't get the food out. Is that misuse? You're following the directions on the box, after all. If they specified "use" of laxatives and diuretics to specifically try and "undo" a binge, then I wouldn't probably be so prickly. It's clear that it's a purging behavior. But misuse? If the idea is to get rid of unclear definitions, I'm not entirely sure they did that.

My other question is this: I thought fasting and exercise were kind of considered forms of purging. I'm not sure what the distinction is--does purging have to involve your mouth or your butt? Sorry to be kind of crass, but I'm still trying to figure that one out. It's one thing to remove the subtypes and just create a "bulimia nervosa" definition that encompasses both purging and non-purging types, but I'm not positive on the wisdom of removing fasting and excessive exercise from the BN criteria.

The DSM-V draft criteria cited a study titled " The Validity and Utility of Subtyping Bulimia Nervosa ," which came to the following conclusions
Another possible reason for the lack of data on individuals with BN-NP may be a problem in diagnosing these subjects. Individuals who would qualify for the diagnosis BN-NP may go unnoticed or be wrongly diagnosed as BED or ED-NOS as a result of incomplete assessment of nonpurging compensatory behaviors. Both dieting and exercising are common in the general population, and are not necessarily pathological. There is no clear criterion to decide at what point the amount of exercising and dieting exceeds a cut-off point and becomes abnormal. This does not mean that nonpurging compensatory behaviors are clinically irrelevant. A number of studies have provided information that both purging and nonpurging compensatory behaviors are important clinical markers, for example, they both have high rates of comorbidity; their frequency is associated with severe maladaptive core beliefs and they are associated with impaired social functioning. The lack of clear definitions of nonpurging compensatory behaviors combined with their clinical relevance highlights the need for better diagnostic criteria.

Although the number of subjects with BN-NP [non-purging bulimia nervosa] is generally lower than that of BN-P [purging bulimia] and BED, in some studies the rates are comparable to, or in favor of, BN-NP, notably for three of the five general population studies. This may be a result of the more standard use of (semi-) structured diagnostic interviews in this type of study, in which the presence of nonpurging compensatory behaviors is routinely checked. Again, this calls for increased attention to the formulation of clear and easy to apply diagnostic criteria for nonpurging compensatory behaviors.
The study called for one of three possible solutions to this subtyping issue
  1. Maintain the current situation by keeping BN-NP as a subtype separate from BN-P as in DSM-IV, that is, a distinction between purging and nonpurging types of compensatory behavior in people who binge eat.

  2. Eliminate nonpurging compensatory behavior as a diagnostic criterion. Individuals
    receiving a diagnosis of BN-NP in DSM-IV would be designated as having BED.

  3. Inclusion of BN-NP in a broad BN category, as suggested by Walsh and Sysko, where a combination of binge eating with only nonpurging forms of compensatory behavior would be considered an atypical form. This would require a clear definition of the normal/abnormal boundaries of food restriction and exercising.
Obviously, the decision was made in favor of option 2.

How the specific vagaries of diagnosis will affect treatment remains to be seen. The irony is that most treatments for BED recommend physical activity--which is fine, but not for someone who uses exercise as a compensatory behavior. The debate isn't settled, and I'm not sure what I would do myself if I got to have the DSM Magic Wand.

Binge Eating Disorder

Binge eating disorder was included, which was a HUGE victory (no pun intended). BED is been fairly well defined for quite some time, and there are specific treatments that can help people struggling with binge eating.

The frequency of binge eating was specified at 1x/week for three months to make it more in line with the BN diagnosis. This seemingly low threshold for binge frequency has gotten some people up in arms. Writes psychiatrist Allen Frances in an article titled "Opening Pandora's Box"
Binge Eating Disorder will have a rate in the general population (estimated at 6%) and this will probably become much higher when the diagnosis becomes popular and is made in primary care settings. The tens of millions of people who binge eat once a week for 3 months would suddenly have a “mental disorder”― subjecting them to stigma and medications with unproven efficacy.
This is certainly a valid concern (a diagnosis should adequately capture all people who are ill with a disorder and none of those who aren't), but just because a diagnosis is more common doesn't mean it's not real. Also, the problems with people being subjected to medication seems more of a problem with our messed-up health care system and non-specialists making rather specialized diagnoses (I wouldn't want my cardiologist trying to diagnose my foot problem) than with the actual diagnostic criteria.

If the criteria for BED was just one binge a week for three months, I'd be much more willing to concede Dr. Frances' point. However, there are other criteria for BED that include feeling overly guilty or disgusted with oneself; the feeling of not being able to stop eating; feeling depressed afterwards; etc. Occasional overeating is unlikely to happen alone and result in "marked distress."

Still, Frances' overall argument is interesting and timely and well worth reading.

Purging Disorder

Rachel at The F Word pointed out the lack of formal inclusion of purging disorder in the DSM-V by highlighting this paragraph from the EDNOS section
The work group is considering whether it may be useful and appropriate to describe other eating problems (such as purging disorder–recurrent purging in the absence of binge eating, and night eating syndrome) as conditions that may be the focus of clinical attention. Measures of severity would be required, and these conditions might be listed in an Appendix of DSM-5. If these recommendations are accepted, the examples in Eating Disorder Not Otherwise Specified will be changed accordingly.
I'm not surprised that purging disorder didn't make it in as a stand-alone diagnosis, not because the data isn't good--it is--but that it's rather new. Rachel has a whole post devoted to purging disorder that is well worth reading, and you can find more studies on purging disorder here .
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