Tuesday, 27 July 2010

Why Dissociative Identity Disorder does not get the treatment it deserves

I am fascinated by Dissociative Identity Disorder (so much so that I wrote my MA’s dissertation on the subject). DID – also known as multiple personality disorder – is roughly what you might expect it to be, given the numerous fictional portrayals of it. Multiple personalities in one body, sometimes with deeply contradictory desires; sometimes existing simultaneously, sometimes alternating. The stories of Dr. Jekyll and Mr. Hyde and Fight Club’s Narrator and Tyler Durden are, handily enough for explanatory purposes, somewhat accurate portrayals of the condition (Fight Club moreso than Stevenson’s tale).

I’m equally fascinated by how rarely DID seems to be a topic for philosophical and psychological research; to me, it seems to be an important phenomena. There are several reasons, I believe, for this paucity of interest. The first is that questions regarding DID are almost inextricably bound with questions of personal identity, and questions about personal identity are a) somewhat unfashionable, and b) bloody difficult. With regards to a), one merely has to compare the number of papers published on personal identity (three thousand this year, according to Google) to those published on, say, consciousness (nearly twenty thousand) to find evidence for the claim. It is admittedly harder to justify b), but a comment by David Chalmers regarding a paper he wrote on the technological singularity is a good indication of its veracity; “I think this is the first time I've written at any length about personal identity, a topic I've largely avoided in the past as it confuses me too much”. Granted that Chalmers is only a single person, but when one of the pre-eminent contemporary philosophers says that a subject confuses him, then we might take it as good evidence that the subject is a complicated one (to say the least).

Aside from personal identity, DID itself is a controversial subject – which, again, might motivate researchers to avoid it. There have been calls to remove it from the APA’s Diagnostic and Statistical Manual of Mental Disorders; arguments for this proposal cite the condition’s lack of certain causation, tautological diagnostic criteria, possible conflicting interests in the diagnosing physicians, and so on (Gharaibeh, 2009). Evidence for DID includes studies which have demonstrated that patients diagnosed with DID possess smaller hippocampal and amygdalar volumes than average individuals (Vermetten et al., 2006), have disrupted memory processes (Dorahy and Huntjens, 2007) and physiological changes as extreme as one personality state being diabetic whilst the other is not (Braun, 1986). I personally feel that there is sufficient evidence to reasonably assume that something is happening in cases of DID, although more research into the condition's exact effects is needed – something which has not gone unnoticed by psychiatrists; Colin Ross (2006), as an example, laments that “the research literature on dissociative identity disorder is smaller than that on many other Axis I and II disorders.”

One quirk of DID research – which, again, might contribute towards many researcher’s reluctance to study it – is its association with some more outlandish claims. Tales of reincarnation and past lives, energy auras, possession; it is not at all unusual to see those working on DID also pursuing research (of some kind) into such topics. It’s probably not absurd to say that there’s a stigma attached to any investigation into parapsychological topics, and DID’s association with such topics, weak as it is, may well damage its reputation. This is, however, effectively pure speculation on my part.

This discussion leads to the eminently reasonable question; why is DID important? Obviously research into the condition is at least mildly important, for if it exists, then there are sufferers who require aid. This, I think, is inarguable, although we might perhaps argue about what forms of treatment are necessary or desirable. Similarly, there are the questions that it raises for personal identity; what is actually going on in these cases metaphysically, if DID is real? One person with a disrupted sense of self? Multiple persons sharing the same body? An answer is not immediately apparent (nor is it apparent after deliberation – the philosophical literature on DID is divided as to whether or not the disorder features multiple persons).

Yet there is another reason why DID requires more research, one that has been hinted at implicitly by such heavyweights as Edelman, Tononi and Dennett; if it is possible for consciousness to be “split”, and for multiple consciousnesses to exist in one body simultaneously, as seems to be the case in certain patients diagnosed with DID, then any mature theory of consciousness must be able to explain such a phenomena. If DID is not a real phenomena, then there is no need for theories of consciousness to account for it (obviously enough). The three authors above have all at least mentioned dissociative phenomena in their writings (Dennett actually authored a particularly interesting article on multiple personality disorder with Humphrey, which I’ve listed in the references), and all ensure that their theories are compatible with DID’s existence. But is ensuring this compatibility necessary? Erring on the side of caution and assuming DID is a real phenomena is, perhaps, an admirable stance – but if we find enough evidence to conclude that it does not exist, then we may be able to streamline potential theories of consciousness.

A possibility, I think, that should be entertained; hence why more research, both empirical and philosophical, into DID should be considered.


Braun, B.G. (1986), Treatment of multiple personality disorder, New York, APA

Dorahy, M.J., & Huntjens, R. (2007). Memory and attentional processes in dissociative identity disorder: A review of the empirical literature. In E. Vermetten, M.J. Dorahy, & D. Spiegel (Eds.), Traumatic Dissociation: Neurobiology and Treatment (pp. 55-75). Arlington, VA: American Psychiatric Publishing, Inc.

Gharaibeh, N. (2009), Dissociative identity disorder; time to remove it from the DSM?, Current Psychiatry, 8, 9, 30-36

Humphrey N, & Dennett D.C. (1989) Speaking for our selves: an assessment of multiple personality disorder, Raritan, 9, 68–98

Ross, C.A. (2006), Dissociative Identity Disorder, Current Psychosis and Therapeutics Reports, 4 (3), 112-116

Vermetten, E., Schmahl, C., Lindner, S., Loewenstein, R.J. & Bremner, J.D., (2006), Hippocampal and Amygdalar Volumes in Dissociative Identity Disorder, American Journal of Psychiatry, 163, 630-636

Tuesday, 20 July 2010

The Perils of Interdisciplinarity

Some of the most engaging research topics today lie firmly on the boundaries between two or more distinct subjects. Research into consciousness encompasses philosophy, psychology, neuroscience, and others; questions about how human behaviour in economic situations seem to be answerable (in part) by psychology, economics, and sociology; research into robotics is aided by computer science, physics and some branches of psychology. Whilst those three choices are - unsurprisingly - ones that interest me in particular, I do not think I am stretching the truth in saying that interdisciplinary topics are hot topics (consciousness, in particular, is particularly popular – a quick Google search informs me that twenty thousand scholarly papers and books on consciousness have been published this year alone); yet just because they are popular topics, we shouldn’t expect them to be easy topics.

Interdisciplinary work is, indeed, fraught with difficulties, solely by virtue of its interdisciplinarity. At the very least, a researcher attempting to straddle two distinct fields has the not-so-simple task of keeping up with research in two subjects simultaneously. Of course, having to keep up with contemporary research is a problem for any scientist or academic, not just those interested in interdisciplinary topics, so this is hardly a difficulty unique to interdisciplinarians. There are two special problems to be overcome when attempting to do such research, however.

The first is a language gap. Quite simply, different subjects require different vocabularies, and it is not often clear to researchers trying to inhabit multiple fields that these different vocabularies exist. My own personal experience with this involves what, by all means, should be a fairly trivial term – the word “paradigm”. In philosophy, the term was introduced by Thomas Kuhn in his work The Structure of Scientific Revolutions to denote a set of scientific assumptions. Kuhn argued that the history of science showed that, in any given scientific subject, one paradigm tended to dominate at any given time, until a sufficient amount of evidence contradictory to that paradigm’s assumptions had built up; at that point, a paradigm shift would occur, and a new paradigm would come to dominate the field. The history of psychology is a good example (although I believe Kuhn did not wish to grant psychology full scientific status); the Freudian, psychoanalytic paradigm shifted to the behaviourist paradigm, which shifted to the cognitive paradigm, which – arguably – has shifted to one of a number of possible post-cognitive paradigms. And so the process, if we wish to agree with Kuhn’s description, will continue. This is the standard definition of “paradigm” in philosophy, and particularly philosophy of science (with apologies if my description of Kuhn’s theory is somewhat vague – when it comes to the philosophy of science, I’m more familiar with Popper’s theories).

In psychology and related behavioural sciences, the word “paradigm” has a far simpler meaning – it refers to an experimental design or procedure. So a study such as Bechara, Damasio, Damasio and Anderson’s Insensitivity to future consequences following damage to human prefrontal cortex would be described as using (and, in Bechara et al.’s case, developing) the Iowa Gambling Task as a paradigm. Pretty simple, but still a minor stumbling block for a philosophy student attempting to branch into psychology – the first time I recall a professor asking me what my paradigm was, I froze; “… the cognitive one?” This answer was not particularly well received.

Yes, a large part of this entry is – in essence – venting about my own hesitation and failure to pick up multiple meanings within the subjects I study. But I am not the only researcher to encounter linguistic difficulties in cross-discipline work. George Loewenstein, a behavioural economist, notes the following in an introduction to his paper The fall and rise of psychological explanations in the economics of intertemporal choice;

“Unlike the other chapters in this book, this paper never appeared in a refereed journal, and not for lack of trying. I think part of the reason that it kept getting rejected at journals was that I missed some of the stylistic elements of papers on the history of economic thought. Subtle, and to my view generally arbitrary, stylistic differences across fields constitute one of the most impenetrable barriers to interdisciplinary work. Like regional dialects, each discipline and even subdiscipline has its own myriad unwritten rules of discourse; violate any one of them and you’re instantly branded an outsider deserving of extra scrutiny and scepticism.” (Loewenstein, 2007, p. 55)

Although my experience is limited, I can’t help but agree with Loewenstein. Whether the “regional dialects” of sub-disciplines are as pronounced as those of separate disciplines, I am uncertain; there is, perhaps, a good argument to be made that they are. Analytic and continental philosophers frequently talk past one another (when they bother to talk with one another at all), and, within psychology, the same could perhaps be said of behaviour analysts (who still adhere to the tenets of methodological behaviorism) and cognitive psychologists.

The second problem I want to discuss is, although less concrete than the first, more significant. Quite simply; who cares about the interdisciplinary work? This problem is summed up succinctly by the following passage, taken from Nick Chater’s review of Patricia and Paul Churchlands’ book, On the Contrary;

“In weaving together threads from philosophy of mind and science with current developments in cognitive science and neuroscience, the question may arise: whose questions are being answered; and according to whose criteria? Nose-to-the-grindstone neuroscientists are likely to find much of the discussion of abstract theoretical and philosophical questions remote from their concerns; whereas philosophers may wonder just how relevant specific discussions of putative computational architectures of the brain are to traditional philosophical concerns. This is inevitable in interdisciplinary work of this kind; and such work provides a stimulus for those in different disciplines to perceive and develop links between disparate areas. Nonetheless, different readers will have very different biases and concerns in reading these essays, purely as a matter of disciplinary background.” (Chater, 2000, p. 616)

Chater seems optimistic that interdisciplinary work will encourage those from particular backgrounds to broaden their own viewpoint. Perhaps this may be the case. I think it possible, however, that those with a particular background will be dismissive of those from other subjects and their quirks; certainly, I have heard many psychologists bemoan the inflexibility of economists when it comes to altering their views on how humans conform to rational norms (in the psychologists’ view - humans don’t), and many philosophers complain that psychologists and neuroscientists just aren’t talking about the right thing when discussing consciousness. There is an all too frequent tendency - when confronted with someone from another field trying to broach a shared topic - for a researcher to say “Well, that’s very interesting, but they’re missing the point. They’re not looking at what’s really interesting/important/tractable about this subject.”

I certainly do not wish to claim that such a tendency is overwhelmingly common. It is, however, another obstacle in the way of interdisciplinary research; one that should not (and, I hope, will not) daunt those interested in such areas, but one that they should certainly note the existence of.

What possible remedies for these two problems? It’s difficult to say. Linguistic differences across fields can, to a certain degree, be diminished by a researcher immersing themselves in both communities (although, apparently, even a dedicated interdisciplinarian like Loewenstein encounters some difficulties). Making researchers in other fields care about the perspective offered by your own is trickier; perhaps the best one can hope for is that at least some will find interest in your data, theories and arguments – although, once again, becoming a part of both communities certainly helps with the matter. Making sure that the perspectives your field offers are genuinely novel and illuminating with regards to a certain difficult topic is, I believe, the best method to engender progress. Such a task is not necessarily easy; but what interdisciplinary work is?


Bechara, A., Damasio, A.R., Damasio, H. & Anderson, S.W. (1994), Insensitivity to future consequences following damage to human prefrontal cortex, Cognition, 50, pp. 7-15

Chater, N. (2000). Contrary views: A review of "On the contrary" by Paul and Patricia Churchland. Studies in History and Philosophy of Biological and Biomedical Sciences, 31, 615-627.

Kuhn, T.S. (1962)
The Structure of Scientific Revolutions, Chicago, University of Chicago Press

Loewenstein, G. (2007).
Exotic Preferences: Behavioural Economics and Human Motivation, Oxford, England, Oxford University Press