A DSM for Psychiatrists?

 

 

No matter what version - the DSM is clearly a flash point for criticism by psychiatrists and non-psychiatrists alike. There are too many diagnoses.  People don’t like certain diagnoses or complain when some categories are eliminated. There are endless debates about diagnostic criteria, reliability, and validity. Categories are a wrong approach and we need dimensions. Philosophers have a field day imagining what the DSM is and making suggestions.  In an early post on this blog, I responded to the philosophical suggestion that the DSM was supposed to be a blueprint for living. Antipsychiatrists have no problem rejecting the entire volume of course because they are stuck in the 1970s with Szasz and maintain that there are no mental illnesses. The more flexible antipsychiatrists reframe this into everyday problems in living another decades old formulation that did not stand the test of time. Others suggest that the DSM exists to make diagnoses that lead to pharmaceutical treatment and make profits for drug companies.  The more legitimate criticism from psychiatrists is focused on the criteria and whether any diagnostic categories exist. Some of that criticism comes full circle back to why a classification system was needed in the first place. Clinical psychiatrists tend to use a fraction of the available diagnoses and in most practices can recall the diagnostic codes without looking them up. In fact, most psychiatrists use the DSM as a reference, pulling it off the shelf for rarely encountered diagnoses and then typically to look up a diagnostic code for coding and billing purposes. 

The title Diagnostic and Statistical Manual – is the first clue about the original intent of the manual and it antedates the psychiatric profession and the APA in the United States by several decades. The abbreviated history is available on the APA web site and several other Internet sites.  Initially it was to determine numbers of people by diagnosis both in the varied mental illness facilities across the country and later in military service. This function was described as administrative but there was also a consensus building aspect in the early 20^th century as diagnoses shifted from a unitary psychosis model to more nuanced.  The advent of the DSM-III was a turning point because it provided atheoretical definitions of disorders that were subsequently adopted by the ICD-9. Subsequent revisions in the DSM-IV and DSM 5 included revisions based on professionals and professional organizations, assigned work groups and their research, and eventually the general public. The original goal of classification and statistics has remained but it is used for various reasons by non-psychiatrists.

There are many examples of non-psychiatric use.  In the legal and political sphere, most states have rationed services for people with severe mental illnesses who are at high risk for hospitalization and other morbidities. Qualifying for those benefits depends on a  DSM diagnosis.  The same is true for state sponsored services for autism and developmental disabilities. In forensic settings experts are called upon to give diagnoses in an adversarial setting.  Disability, veteran’s benefits, and worker’s compensation are all linked to diagnoses.  All medical billing to insurance companies and government payers depend on DSM equivalent diagnostic codes in the ICD-11. Managed care companies ration care based on many of these codes by refusing to cover them. None of these functions were designed as an original intent for the diagnostic manual.

Heterogeneity – either explicit or implicit is another frequent criticism of the manual. Human biology and the biology of diseases and disorders teaches us that the etiopathogenesis of illnesses is diverse. There are many possible underlying biological and nonbiological causes.  Many genes and lesions can often lead to the same apparent presentation or phenotype.  That lead to the idea of intermediate phenotypes or endophenotypes to get a more consistent population to study but that has only been partially successful. The DSM was never designed to biologically classify mental illnesses, but DSM diagnoses are used for studies of biology and pharmacology. Other systems have been suggested for that purpose – most notably the RDoC system, but so far it has not exhibited any widespread success.  There is no reason to think that a verbally based system will accurately describe biologically based illness whether those descriptions are in the DSM or RDoC.

Apart from classification for statistical, administrative, and planning purposes what good is the DSM to psychiatrists? I recently saw it criticized for not including enough psychopathology. The criticism was bitter and partisan but apart from some very basic definitions the DSM is not a course in psychopathology.  All psychiatric residents need to be taught psychopathology to the point that they are experts in it. That will never happen from reading the DSM. It also doesn’t happen from reading a psychopathology text or taking a college course in psychopathology.  It happens from seminars, reading, and clinical experience – discussing psychopathology with colleagues, supervisors, and instructors.  It happens from learning in treatment relationships with people who have psychopathology not just a list or criteria but experiencing firsthand the interpersonal aspects. The DSM explicitly states that it is for use by trained professionals and that it can be used to facilitate communication between trained professionals.  

The DSM is clearly not a treatment manual of any kind. That is why I have always found the charge that it is a source of prescriptions for the pharmaceutical industry ludicrous.  There are roughly six times as many prescribers of psychiatric drugs as there are psychiatrists and the only medication in that category that is more likely to be prescribed by psychiatrists is lithium. It is easy to speculate that the prescribing patterns of that larger group are not contingent about what is in the DSM.

What about the diagnostic side and what psychiatrists need? Although there was some criticism that the neo-Krapelinians have had too much influence on the manual it is time to acknowledge that verbal descriptions have come to their logical limits. It is also time to acknowledge that psychiatrists need to know a lot more about medical diagnoses in general in order to function in a medical environment. If medical conditions are in the differential diagnosis – how many medical conditions do psychiatrists need to know about and diagnose?  Every psychiatrist I know has stories about medical conditions that were referred to them as a psychiatric disorder where they made the correct medical diagnosis. They are typically conditions from neurology, endocrinology, and infectious disease but also general medical conditions like diabetes mellitus, hypertension, and atrial fibrillation. Approaches I have seen in other specialties include lists of conditions that the trainee or practitioner needs to know about.  That is a useful approach but lists like that in a DSM are likely to raise objections about medicolegal risk and that a larger recipe book is being made for what it takes to be a psychiatrist. There are also many psychiatrists in settings where medical assessments are impossible, where they are referred out, or where the practitioner may feel inadequately trained. I see all of those reasons as being an opportunity to advance the quality of psychiatric treatment.   

A related issue is the diagnostic process in psychiatry as opposed to the rest of medicine.   Nassir Ghaemi, MD had a recent commentary about this on his blog suggesting that the DSM approach prioritizes comorbidities rather than differential diagnosis like the rest of medicine.  He describes the typical pattern matching that occurs early in the process and suggests that the differential diagnosis point, the DSM encourages listing all of the comorbidities rather than going through a differential diagnosis process.  In other words there is a lack of a hierarchical process. 

That has not been my experience. Granted – I may be a more medically oriented psychiatrist than most (but then again had 20 colleagues doing the same work) – but when I see a patient the universe of diagnoses are all possible both in and outside the DSM. The number one priority was making sure that a life threatening medical condition was not misdiagnosed as a psychiatric disorder.  Every physician can recall being taught about differential diagnosis and having to write an exhaustive list for the first few Internal Medicine inpatients. That process illustrated that a lot of the “rule outs” occurred as a mental exercise and really did not need to be written down. By the end of that rotation the differential diagnosis list collapse from the low double digits to the low single digits. There was also a triage element based on the more pressing problem or diagnosis.   A DSM for psychiatrists could make this process explicit, discuss the cognitive aspects of pattern matching and completion necessary for generating hypotheses in the differential diagnosis, the differences between differential diagnosis and comorbidity, and probabilistic considerations in selecting the preferred diagnosis. It would potentially have training implications because in order to optimize the pattern matching required - adequate training experiences need to be supplied to develop those skills. 

A DSM for psychiatrists needs to be much more information intensive in terms of research on validators, psychiatric genetics, multiomics, endophenotyping, drug mechanisms of action, and biological markers for each category.  A typical response to that suggestion is "Well there are no biological markers, labs tests, etc."  I don't find that to be a compelling argument when I think about what is currently being ignored.  We are on the cusp where more of that information is becoming relevant and we are past the point where much relevant information can just be dismissed. Any concern about cost of a more extensive manual can be dealt with by placing it online for subscribers. This may seem like a significant task given the accumulating information, but it is time the APA and research leaders in psychiatry to realize that the task has changed.  Psychiatrists are different from other physicians and other mental health professionals.  Psychiatrists need the technical information to provide quality care and compete against other systems that claim to know more about psychiatry and medicine than they do. Time to adjust to that reality and have the necessary internal debates first.

That concludes my suggestion for a DSM for psychiatrists, but I am open to more suggestions.  And for the record I am suggesting two different publications instead of a general manual full of qualifiers about expertise.  We need a manual for experts and another one like the current version - for everybody else.

 

George Dawson, MD, DFAPA

References:

1:  Horwitz, A.V. (2014). DSM - I and DSM - II . In The Encyclopedia of Clinical Psychology (eds R.L. Cautin and S.O. Lilienfeld). https://doi.org/10.1002/9781118625392.wbecp012

2:  Kim YK, Park SC. Classification of Psychiatric Disorders. Adv Exp Med Biol. 2019;1192:17-25. doi: 10.1007/978-981-32-9721-0_2. PMID: 31705488.

3:  Cooper R, Blashfield RK. Re-evaluating DSM-I. Psychol Med. 2016 Feb;46(3):449-56. doi: 10.1017/S0033291715002093. Epub 2015 Oct 16. PMID: 26470724.

4:  Shorter E. The history of nosology and the rise of the Diagnostic and Statistical Manual of Mental Disorders. Dialogues Clin Neurosci. 2015 Mar;17(1):59-67. doi: 10.31887/DCNS.2015.17.1/eshorter. PMID: 25987864; PMCID: PMC4421901.

5:  Blashfield RK, Keeley JW, Flanagan EH, Miles SR. The cycle of classification: DSM-I through DSM-5. Annu Rev Clin Psychol. 2014;10:25-51. doi: 10.1146/annurev-clinpsy-032813-153639. PMID: 24679178.

6:  Grob GN. Origins of DSM-I: a study in appearance and reality. Am J Psychiatry. 1991 Apr;148(4):421-31. doi: 10.1176/ajp.148.4.421. PMID: 2006685.

Supplementary:

It has been suggested that a hierarchical approach informs the usual differential diagnosis exercise but it may be the application of the parsimony principle. To me there is an open question about how well parsimony works for complex biological systems.

Photo Credit:  Eduardo Colon, MD