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Library of Alexandria: The Transition Toward More Biology Based Methodology of Diagnosis in Mental Health

December 23, 2012

The Transition Toward More Biology Based Methodology of Diagnosis in Mental Health



                          


Biopsychology, psychobiology, behavioral neuroscience, physiological psychology, neurobiologist, neuropsychology, neuroscience; these are all different terms for describing fields of study that evaluate the relationship between the physical and the psychological. The study of this relationship has been chipping away at this distinction and is beginning to make it seem more and more like a false dichotomy. Some even go so far as to claim that neuroscience is “eroding the idea of free will” ("Free to choose?", 1996). As these fields continue to evolve and mature their explanatory power will expand deeper and deeper into neurophilosophy and change what we think of when we discuss mental illness.

The idea of a connection between the mind and the body is an old one. Carlson, in his textbook Physiology of Behavior, notes that the study of this relationship dates as far back as ancient Greece. Although the speculation of the times was crude and often inaccurate, some great philosophers were on the right track. Hippocrates (460-370B.C.E) properly identified the brain as the source of emotion while many of his counterparts of the time believed the heart to be the seat of emotion (a notion that is still evident in popular language today). Skipping ahead a great many years, the speculations of Rene Descartes helped to form the foundation of modern neuroscience. Descartes understood the human body to be nothing but an extremely complex machine. His rudimentary understanding of the influence environment has on behavior lead him to coin the phrase “reflexes”. Although Descartes ended up being demonstrated to be wrong in his explanations of the ways the mind and the body interact his ideas laid the ground work and served as a starting point for much future research. (Carlson, 2007)
The official collection of statistical data on mental illness within the United States began with the 1840 census in which the frequency of a single category (idiocy/insanity) was recorded. Focus was maintained on statistical data of mental illness until shortly after World War II. At this time the U.S. Military and the VA began to develop a classification system which was later circulated to a small percentage of the APA for commentary. A portion of those comments were used to create the first edition of the Diagnostic and Statistical Manual (Greenberd, Shuman, & Meyer, 2004). “The DSM-I was the first official manual of mental disorders to focus on clinical, as opposed to statistical, utility” (Greenberd, Shuman, & Meyer, 2004). Lacking the technology and understanding for biologically based diagnosis for much of mental illness (which is by and large still the case today) the first edition of the DSM necessarily focused on the symptomology of mental illness. This methodology has persisted and is the basis for some criticism of the DSM. The validity of the current methods of diagnosis utilized within the DSM is challenged by critics who note that unlike the majority of illnesses, patients diagnosed using the DSM often do not fit neatly into a single category or will sometimes fit into more than one.  Some professionals feel that the true utility of diagnosis based on symptoms rather than etiology is suspect (Mood Letter, 2008), despite its success to date. Further, under current methods a mental disorder requiring 5 of 9 symptoms for diagnosis may diagnose 2 people who share only one common symptom with the same disorder. Surely the underlying biological mechanisms behind their dysfunction are extremely, if not entirely, different.  Under the current model these patients, diagnosed with the same disorder despite their biological differences, will be treated for their disorder, not the causes of their unique symptoms.
            In a significant paper published in 1992, Jerome C. Wakefield challenged the DSM’s definition of “mental disorder”. Wakefield analyzed the definition of mental disorder utilized in the DSM-III and summarized it as the following: “A mental disorder is a mental condition that (a) causes significant distress or disability, (b) is not merely an expectable response to a particular event, and (c) is a manifestation of a mental dysfunction” (Wakefield, 1992). Wakefield goes on to compellingly argue that this could all be more simply and effectively defined as harmful dysfunction and in a another paper goes on to describe harmful dysfunction as the following: “harmful is a value term based on social norms, and dysfunction is a scientific term referring to the failure of a mental mechanism to perform a natural function for which it was designed by evolution” (Wakefield, 1992). Despite lots of criticism from the psychological and psychiatric communities the author of the official DSM-III definition of mental illness comes to Wakefield’s defense and describes “Wakefield's HD formulation as a major conceptual advance over previous attempts (including mine) to define medical and mental disorder” (Spitzer, 1999) . While the DSM-IV expands on the DSM-III definition it is not until the upcoming DSM-V that the official definition of mental disorder includes the following: “reflects an underlying psychobiological dysfunction” (APA, 2010).  I major step towards biology based diagnosis.
Utilizing Wakefield’s definition of disorder within the context of mental illness raises some serious issues with the historical and current methodology of symptom centric diagnosis and the necessary diagnostic categories that arise from this approach. If mental disorders are in fact the result harmful failures of internal mechanisms it makes sense to identify those internal mechanisms and treat the failures in those processes, which is often not the case today. Further, new evidence seems to validate the old criticisms of the DSM’s approach to diagnosis. “Today's research is finding that some disorders have similar symptoms but are actually very different in their underlying biology and may respond differently to different treatments” (Mood Letter, 2008). Now not only do some patients share only a limited number, or in some cases a single symptom, but researchers are finding that even among shared symptoms the underlying biological causes may be very different.  This raises a whole world of issues regarding not just diagnosis but treatment as well.
The current director of the National Institute of Mental Health (NIMH), Thomas Insel, is a strong proponent of a more biologically based approach to the diagnosis of mental illness. In January of 2010 Insel criticized the diagnosis of mental illness stating that “it has become increasingly clear that most of our diagnostic categories are heterogeneous, and most of our patients have “co-morbid” conditions. The Diagnostic and Statistical Manual of Mental Disorders, or DSM, has yielded improved reliability, but validity will require an approach based on pathophysiology, not clinical consensus” (Insel, 2010).  Insel goes on to describe a new initiative by the NIMH titled The Research Domain Criteria (RDoC). This initiative is intended to “develop neuroscience-based criteria for classifying mental disorders” and hopes to provide “translational scientists with new ways of organizing research based on dimensions of cognition or behavior that are linked to specific neural systems” (Insel, 2010).
In the NIMH’s web portal for the RDoC initiative it discusses current methodology stating that “in antedating contemporary neuroscience research, the current diagnostic system is not informed by recent breakthroughs in genetics and molecular, cellular and systems neuroscience.” It goes on to describe the project as the following: “RDoC is intended as a framework to guide classification of patients for research studies, not as an immediately useful clinical tool. While the hope is that a new way forward for clinical diagnosis will emerge sooner rather than later, the initial steps must be to build a sufficient research foundation that can eventually inform the best approaches for clinical diagnosis and treatment. It is hoped that by creating a framework that interfaces directly with genomics, neuroscience, and behavioral science, progress in explicating etiology and suggesting new treatments will be markedly facilitated.”
The criticism of this new approach seems to stem from a few perspectives although this largely stems from an antipsychiatry and anti-psychopharmacological perspective.  The journal Ethical Human Psychology and Psychiatry in which the publishers attempt to examine “all the ramifications of the idea that emotional distress is due to an underlying organic disease that is best treated with pharmacological therapy” (Springer Publishing)  tends to be critical of biopsychology. The journal was co-founded by Peter R. Breggin who is a major critic of conventional psychiatry and psychiatric medications in general.  Another of the criticizing perspectives comes from a dualist approach to the mind and body that advocates the mind is separate from neurobiology and thus at least some mental illness exists within the mind rather than the brain.  There is also opposition from the field of Psychiatry, Wakefield however gives us good reason to expect such opposition by pointing out that “Psychiatry to some extent depends for its existence as a medical specialty on the distinction between mental and somatic disorders” (Wakefield, 2006).  S.E. Hyman argues for the development and utilization of new methods of diagnosis and that these will prove to be vital tools in the future. However, they make compelling arguments that it is likely “premature to bring neurobiology into the formal classification of mental disorders that will form the core of the DSMV” (Hyman, 2007). Hyman goes on to state “it is not too early to use
neurobiology as a central tool to rethink the current approach to mental disorders, and to begin some careful experiments that could liberate science from the unintended consequences of reifying the current diagnoses that probably do not mirror nature” (Hyman, 2007).
Going forward it seems inevitable that we will progress closer to more precise biological basis of diagnosis of mental illness. Evidence indicates that all stimuli detected by the brain have direct physiological effects on the brain.  What many opponents of the progression to biological based diagnosis fail to recognize is that because social and experiential stimuli may contribute to the development of disorder those same factors will also continue to be viable treatment options in many cases even after our understanding of the associated biology matures. A more complete biology based understanding of the brain and mental illness does not necessarily imply a transition to purely pharmaceutical or neurosurgical interventions.  Surely many of the current therapy based approaches will gain valuable knowledge from an increased understanding of the biology of the disorder they hope to treat as well as knowledge of the biological impact of their therapies.  It is important to remember that projects such as RDoC are not intended to be immediately utilized in clinical settings and do not even aim to replace, but to supplement, current psychiatric methods.


References

APA, . (2010). Definition of a mental disorder: proposed revision. Retrieved from http://www.dsm5.org/ProposedRevisions/Pages/proposedrevision.aspx?rid=465#
Free to choose?. (1996, December 19). The Economist , Retrieved from http://www.economist.com/node/8453850?story_id=8453850
Carlson, N.R. (2007). Physiology of behavior. Pearson.
Greenberd, S.A, Shuman, D.W., & Meyer, R.G. (2004). Unmasking forensic diagnosis. International Journal of Law and Psychiatry, (27),
Mood Letter. (2008, May 1). What is the dsm-iv? the diagnostic and statistical manual of mental disorders. Retrieved from What is the dsm-iv? the diagnostic and statistical manual of mental disorders. (2001, May 1). Retrieved from http://www.moodletter.com/DSM.htm
Wakefield, J.C. (1992). Disorder as harmful dysfunction. Psychological Review, 99(2), 232-247.
Wakefield, J.C. (1999). Evolutionary versus prototype analysis of the concept of disorder. Journal of Abnormal Psychology, 108(3), 374-3
Wakefield, J.C. (1992). The concept of mental disorder. American Psychologist, 47(3), 373-388.
Spitzer, R.L. (1999). Harmful dysfunction and the dsm definition of mental disorder. Journal of Abnormal Psychology, 108(3), 430-432.
Insel, T. (2010, Januar 8). Looking forward in 2010 [Web log message]. Retrieved from http://www.nimh.nih.gov/about/director/2010/looking-forward-in-2010.shtml
Springer Publishing, . (n.d.). Ethical human psychology and psychiatry. Retrieved from http://www.springerpub.com/product/15594343
Wakefield, J.C. (2006). What makes a mental disorder mental?. Philisophy Psychiatry and Psychology,
Hyman, S.E. (2007). Can neuroscience be integrated into the dsm‑v?. Nautre Reviews: Neurscience, 8, 725-732.

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