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Information regarding the upcoming DSM V

In Neuropsychology, Psychiatry, School Psychology on Wednesday, 26 September 2012 at 08:00

DSM-5: Finding a Middle Ground

Nassir Ghaemi, MD

DSM-5: Validity vs Reliability

This year’s American Psychiatric Association (APA) annual meeting was probably the last before the publication of theDiagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5), scheduled for May of next year. Hence, there was a sense of tense uncertainty in the many sessions addressing potential DSM-5 revisions.

DSM-5 Task Force Vice Chair Darrel Regier headed a symposium reviewing results of field trials on the reliability of proposed DSM-5 criteria. The trials were meant to assess whether clinicians can use the proposed criteria consistently and provided kappa values for the individual proposals.

Kappa values reflect the agreement in a rating by 2 different persons, after correction for chance agreement. From a statistical perspective, kappa values greater than 0.5 are generally considered good. As an example, 70% agreement between raters translates to a kappa value of 0.4.

Results of the field trials showed good agreement for such disorders as major neurocognitive disorder, autism spectrum disorders, and post-traumatic stress disorder, with kappa values of 0.78, 0.69, and 0.67, respectively. However, poor kappa values, in the range of 0.20-0.40, were reported for commonly diagnosed conditions, such as generalized anxiety disorder and major depressive disorder. All of the observed kappa values in the DSM-5 field trials translate to agreement between clinicians of around 50%.

Is this good or bad? A recent editorial[1] by DSM-5 leaders makes comparisons with other medical settings, and the claim is that most medical diagnoses involve diagnostic kappa values similar to those in the DSM-5 field trials. I spoke with prominent psychiatrists at this year’s meeting who were involved in some of these DSM studies and discussions; they expressed unhappiness with the kappa values in DSM-5 field trials, and some pointed out that kappa values in the DSM-III were higher.

So, the reliability of DSM-5 criteria seems to have declined compared to DSM-III. Is this a problem? It might be, but it might not be.

Reliability only means that we agree. It doesn’t mean that we agree on what is right. Validity is a separate issue. It could be that criteria are changed so that they are more valid — that is, actually true — but this could increase unreliability; raters might have to use, for instance, some criteria that are less objective and hence less replicable.

We will see. DSM-5 might be more valid but less reliable than DSM-IV and DSM-III. If so, that’s progress, in a way.

It is also important to think about other medical studies with low reliability. We should be careful about criticizing certain diagnoses, such as bipolar disorder (as some have[2]), without an awareness that this is the case for almost all our diagnoses. The problem of reliability is a general one, not a problem about claimed “overdiagnosis” of some conditions.

In my view, it is definitely time for a new edition of DSM; we can’t pretend that something written almost 2 decades ago is anywhere near up to date, with a generation of new research. Some of the proposed changes in DSM-5 — for example, the inclusion of antidepressant-induced mania as part of bipolar disorder; the inclusion of dimensions for axis II personality conditions; and the removal of nosologically nonspecific axis II diagnoses, such as “histrionic” personality — are consistent with an update based on convincing new research. But other changes, such as the wish to discourage the diagnosis of childhood bipolar disorder by making up a new category based on limited data (temper dysregulation disorder), merely repeat the mistakes of DSM-IV. Making up diagnoses because we don’t like others is not a scientifically sound way to revise a profession’s diagnostic system, and it won’t serve us well for the next 20 years.

But DSM-IV Has Limitations, Too

Also at this year’s APA meeting, Steven Hyman, a psychiatrist and neurobiology researcher who is former head of the National Institute of Mental Health, gave a plenary lecture on DSM-5 that was refreshingly honest in its appreciation of the limitations that the DSM-IV has placed on research. Rewinding to DSM-III, from the 1980s, he made the point that although that edition was a major advance, it is now out of date, and that DSM-IV, which merely continued the basic DSM-III structure, needs major changes. “The DSM-III was a brilliant document that could not have foreseen the science. It’s time to move on scientifically,” said Hyman.

Hyman noted that DSM-III actually hinders science. Researchers have difficulty getting funding from the National Institutes of Health or publishing papers that go outside DSM criteria: “For example, it was very hard to get a grant to test the hypothesis that maybe the apparent comorbidity of multiple anxiety disorder and mood disorders was just that there was a single underlying process or single disorder that got expressed with different symptom complexes in different times in life.”

There was a name for that condition — neurotic depression — and Sir Martin Roth, the great British psychopathologist, warned repeatedly in the 1970s and 1980s that it would be a mistake for DSM-III to remove it. DSM-III made that mistake, and the field has since acted like it would be a sin to study the matter any further.

There are many examples of this ilk in DSM-III and DSM-IV. Some who are upset with proposed changes in DSM-5 are diagnostic conservatives who seem to think that all our questions were answered in 1980 and 1994.

Dr. Hyman has been influential in designing the new Research Domain Criteria (RDOC), an attempt to create a DSM for research that begins with biological, rather than clinical, terms. I agree with the need for a DSM for research, but I don’t think our biological knowledge is advanced enough yet — despite all the advances that have been made — to build a diagnostic system from them, even for research purposes.

I think we should have a new DSM just for research: a system of Research Diagnostic Criteria (RDC), like what was created in the 1970s that led to DSM-III to begin with. I’ve started that process with my colleagues in the world of bipolar disorder research. We will publish a new RDC for bipolar disorder within the coming year — before DSM-5, I hope. If we do so, I hope that colleagues in other specialties in psychiatry will produce similar RDCs.

With these new publications, psychiatry may then be in a position for real advance. We will then have 3 nosologies, all complementary to each other and able to improve the others:

  1. DSM-5: a nosology based on a mix of research, economic concerns, social preferences, and professional consensus that is used for basic practice, insurance reimbursement, and short-term consensus.
  2. RDOC: a nosology based solely on biological research that is used for research.
  3. RDC: a nosology based solely on clinical research that is used for research.

In summary, DSM-5 is on its way, and May 2013 is as good a date as any for its publication. In some places, it will be a much-needed advance over the now-outdated DSM-IV. But in other places, it keeps old categories that are not as well proven as they should be, and it even adds a few new categories that are mainly based on professional, economic, and social concerns rather than on sufficient scientific evidence.

References

  1. Kraemer HC, Kupfer DJ, Clarke DE, Narrow WE, Regier DA. DSM-5: how reliable is reliable enough? Am J Psychiatry. 2012;169:13-15. http://ajp.psychiatryonline.org/article.aspx?articleid=181221 Accessed May 15, 2012.
  2. Zimmerman M, Ruggero CJ, Chelminski I, Young D. Is bipolar disorder overdiagnosed? J Clin Psychiatry. 2008;69:935-940.

Retrieved from: http://www.medscape.com/viewarticle/764740?src=ptalk

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  1. Awesome, your blog is very informative.
    Simply Jyune
    xoxo

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