I recently returned from the International Conference on Eating Disorders, which was held this year in Montreal. It’s my first time attending the conference, and I’m very pleased to have had the opportunity. The ICED is the annual conference for the Academy of Eating Disorders, and is attended by some of the best researchers and clinicians in the eating disorder field. The conference took place over 3 ½ days, and included numerous presentations and educational opportunities. I learned more than I could possibly put into a blog post, so instead, I thought I would comment on the theme of the conference, “Crossing Disciplinary Boundaries in Eating Disorders”.

The conference was kicked-off with a keynote address by renowned psychologist David Barlow. Dr. Barlow is well known for his research of cognitive-behavioral treatments for anxiety disorders, and focused his discussion on the idea that it may be more effective to investigate psychiatric disorders from the perspective of what they have in common, versus what separates them. He termed this “lumping” versus “splitting” and noted that the latest version of the DSM, DSM-5 has continued the trend of “splitting”. Interestingly, DSM-5 is slated to be released this month, and the director of the NIMH has gone on record as saying NIMH is moving away from researching psychiatric disorders using the DMS-5 nosology. His comments provoked a response by the American Psychiatric Association, who basically said, “This is the best we can do until you researchers give us better evidence.” Meanwhile, the shortcomings of DSM-5 have led some to question the biomedical framework for psychiatric disorders, while others argue that it encourages mental health practitioners to pathologize normal human behavior. I think this controversy is unfortunate and only serve as fodder for the anti-psychiatry movement. The mental health field has worked extremely hard at reducing the stigma around seeking treatment for mental illnesses. It would be devastating if the current DSM-5 controversy negatively impacted this effort.

Eating disorders, in my opinion, are an excellent example of the “lumping” versus “splitting” issue. Research has shown that for many individuals with eating disorders, their diagnostic presentation changes with time. It is not unusual to have someone develop Anorexia Nervosa during adolescents, but then continue to struggle with a variety of eating disordered behaviors over the course of the lifetime, including binging and purging. In fact, most individuals with an eating disorder end up in the Not Otherwise Specified category because, while clinically impaired, they do not meet the specific criteria for either Anorexia Nervosa or Bulimia Nervosa. This would suggest that there are strong commonalities between disorders that are conceptualized as being separate. On the other hand, Binge Eating Disorder, which is being added to DSM-5, may be more distinct from AN & BN. For example, prevalence rates for men are much higher for BED than for AN or BN and there does not seem to be the diagnostic “crossover” that occurs with AN & BN. However, the inclusion of BED in DSM-5 does continue the trend of “splitting” diagnostic categories, which may or may not be helpful to our understanding of eating disorders.

One of the fascinating things about eating disorders is the interplay between biology and psychology. A classic study informally referred to as the Keys Study showed how starvation can induce behaviors that mimic Anorexia Nervosa (the ethics of the study are a different story). It was one of the first studies to clearly demonstrate the biological underpinnings of eating disorders and how starvation can negatively affect psychological functioning. Another such example is the research that suggests there are different personality traits associated with Anorexia Nervosa and Bulimia Nervosa and how they may impact the development of these illnesses. We desperately need better research into the biological basis for personality traits and how these relate to psychiatric disorders. I think a major shortfall of the DSM-IV was the artificial separation of personality disorders and mental illness. The reality is that the two are intertwined and likely share common pathophysiology in the brain. So I am firmly in the “lumping” camp at this point, and hope that the NIMH RDoC effort helps us develop better dimensional models of psychiatric disorders that delineate the underlying biological mechanisms and associated environmental factors.