This week's Science Times in the NY Times featured a profile of psychologist Russel Hurlburt, who studies the inner experiences of people with mental illness. For many mental illnesses, the DSM spells out the symptoms that people have, but it doesn't really describe what it's like to have a particular illness. For that matter, knowing what cancer is and how to treat it isn't the same as knowing what it's like to have cancer and undergo treatment.

From the profile:

After hundreds of introspective interviews, Dr. Hurlburt still hesitates to generalize from his findings. But he has observed that the basic makeup of inner life varies substantially from person to person.

“My research says that there are a lot of people who don’t ever naturally form images, and then there are other people who form very florid, high-fidelity, Technicolor, moving images,” he said. Some people have inner lives dominated by speech, body sensations or emotions, he said, and yet others by “unsymbolized thinking” that can take the form of wordless questions like, “Should I have the ham sandwich or the roast beef?”

In a 2006 book, “Exploring Inner Experience,” Dr. Hurlburt suggests that these differences may be linked to personality and behavior. Inner speakers tend to be more confident, for example, and those who think in pictures tend to have trouble empathizing with others.

Differences in thinking style may also help explain some aspects of mental illness. In studies conducted with Sharon Jones-Forrester and Stephanie Doucette, Dr. Hurlburt found that bulimic women experienced a clutter of simultaneous thoughts that could often be cleared by purging.

Which makes sense to me. If you want to consider exercise a form of purging, I can definitely attest that purging slowed my racing thoughts and really calmed me down. Purging (granted, I have purged in more ways than exercise, but that was my most common and recent form of purging) was almost like dissociating. It's not exactly the same, and I wasn't dissociated while exercising/purging, BUT my brain also felt very separate from my body, almost like it was observing me running or pedaling or whatever.

I tried looking for any publications by Jones-Forrester and Doucette, but it appears that their work on the inner experiences of people with bulimia consisted mainly of doctoral dissertations under Dr. Hulburt. I found the abstract of Jones-Forrester's thesis, which reads:

Inner experience is of crucial importance in bulimia---clearly something experiential leads individuals to binge or purge. We used Descriptive Experience Sampling (DES) to examine the inner experience of bulimia in 5 participants, replicating Doucette (1992). Our participants' inner experiences were largely consistent with Doucette's but were substantially different from what is assumed by the non-DES literature: our bulimic participants had a consistent fragmentation of attention, hypersensitivity to the sensory aspects of experience, affect that is poorly differentiated and often confused with cognition, and a striking lack of cognition overall. These results suggest that DES can be a powerful tool to challenge the assumptions of the extant literature and to expand our understanding of bulimia.

Hurlburt cited the research of Doucette in his 1993 book "Sampling Inner Experience in Disturbed Affect," sections of which are available on Google Books. From this book:

Multiple Inner Experience is the simultaneous occurrence of a few or many separable, identifiable inner happenings, all taking place in inner experience at the moment of the beep. One of the most striking findings in our study of bulimics was that Multiple Inner Experience was a frequent characteristic of the inner experience of all our bulimia subjects. This is in sharp contrast to the findings of other researchers sampling non-bulimic populations, where the phenomenon of Multiple Inner Experience occurs occasionally but is rare (an exception is the example of Borderline Personality described in Chapter 14). In contrast with other subjects, however, Multiple Inner Experience was the rule, rather than the exception, among our bulimics: the frequency ranged from 40% to 100% within our individual bulimic subjects.

It was also the case that, for our bulimic subjects, the presence of Multiple Inner Experience was directly related to the degree of bulimic symptoms: the more actively bulimic the subject, the more multiple the inner experience. This was true both when considering the percentage of a subject's samples containing Multiple Inner Experience (the more actively bulimic, the higher the percentage) and also when considering the multiplicity of experience at any given sample (the more actively bulimic, the higher the number of separate experiences which were reported to be simultaneously occurring at any one beep).

{snip}

A third characteristic experienced by our bulimic subjects was the relatively blurred distinction between thought and feeling. Our bulimics frequently seemed to "think their feelings" or "feel their thoughts." By contrast, most normal subjects in our sampling were very clear about the distinction between thinking and feeling. Even on those occasions where they have difficulty providing the experiential details of a thought...most non-bulimic subjects have no doubt that the thought is a "cognitive" or "mental" experience; the same is true for affective experiences. An exception is our anxious subjects (see Chapter 13), who also at times had difficulty distinguishing between affect and cognition.

{snip}

The intensity of the urge to purge seemed more related to the heightened multiplicity of thoughts and feelings than to the content of food or weight.

(Emphasis mine)

I find this work of Hurlburt, Doucette, and Jones-Forrester to be absolutely fascinating, and I really wish there was more peer-reviewed research on the subject. Still, this work may help fill in the gaps between what we know about bulimia and how BN is experienced.