We know a lot more about eating disorders than we did ten or twenty years ago. But with that knowledge comes the rather sobering fact that we still don't know a whole lot. At Lobby Day 2008, Dr. Cindy Bulik said that we lacked even basic epidemiology on the prevalence of EDs in the general population. People have extrapolated and guessed, but that's kind of like saying you live in the US somewhere west of NYC and east of LA. It doesn't exclude a whole lot.

Besides the epidemiological data that we lack, there is also the problem of how to define and diagnose eating disorders. The gold standard is the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition* which basically describes each "mental disorder" as a syndrome. That is, the DSM doesn't go into detail as to what causes the illness, which is unlike many other medical conditions (i.e., the definition of tuberculosis includes the identification of the causative Mycobacterium tuberculosis), but instead just describes signs and symptoms that can be identified by doctor and/or patient. The Wikipedia entry on "syndrome" says that the word

is most often used to refer to the set of detectable characteristics when the reason that they occur together (the pathophysiology of the syndrome) has not yet been discovered.

In simple parlance, we don't know a whole lot about what causes the disease, but we can identify it. Although we know a lot more about what causes eating disorders, we don't know the exact sequence of events, nor do we know what factors are necessary to result in the development of an eating disorder.

Which is why I think that the recent paper titled "Clarifying criteria for cognitive signs and symptoms for eating disorders in DSM-V" is so important. If we can't find a specific bulls-eye to diagnose an eating disorder, then we can at least make that bulls-eye as small as possible so that people who have eating disorders can receive a proper diagnosis.

The researchers, led by Anne Becker at Harvard, took on some of the most profound and disabling aspects of eating disorders: the underlying cognitions.

The literature supports several reasons that individuals with an eating disorder may not endorse cognitive symptoms, despite their presence. These include limited insight, minimization, or denial, as well as intentional concealment related to perceived stigma, social desirability, or investment in maintaining behavioral symptoms. We also identified reasons that the word "refusal" in AN criterion A may render its application problematic.

In my opinion (and this is getting back to A's excellent comment on yesterday's post), it's the cognitions, not the weight, that ultimately delineates people into having anorexia or not.** Not that the behaviors are irrelevant--far from it. But thoughts and behaviors exist in this enormous feedback loop, and both must be changed for ongoing and lasting recovery.

Even using cognitions to define EDs can be problematic due to the prominence and prevalence of dieting and food phobia in our culture. We need to get better at making these distinctions, since I doubt our obese-o-phobic society is going anywhere.

*This was on my list of recommended books on Amazon the other day, causing great laughter and hilarity on my part.

**I am less familiar with how this might apply to bulimia, and I am also tired so I won't tackle it in this post. But I think the frequency of binge eating and purging is important- one episode is definitely problematic, but how can we say that it's a disorder? Daniel LeGrange's group found an actual clinical difference between adolescents with full-blown BN or sub threshold BN. How significant that is, I don't know.