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Book Review: The Diagnostic System

While it’s true that many illnesses are foreign to the average person, many of the core symptoms of mental illness are familiar to virtually everyone.

“Not only does the public have a reasonable sense about what the symptoms of mental illness feel like, it also has some intuitive grasp about what causes them,” writes Jason Schnittker.

In his new book, The Diagnostic System: Why The Classification Of Psychiatric Disorders Is Necessary, Difficult, And Never Settled, Schnittker explores the evolution of the manual we use to understand mental illness – the Diagnostic and Statistical Manual.

Schnittker explores the often confusing and seemingly contradictory processes of defining criteria of mental illnesses, helping readers appreciate that a fluid approach is an adaptive strength of mental health professionals, and one that is necessary to boost our understanding of mental illness.

To understand how we develop a framework for understanding mental illness, we must appreciate that the way clinicians, scientists, and the public think about mental illness seek to serve different needs, yet cannot be segregated.

“The science of psychiatric disorders, for example, proceeds from how clinicians define disorders. And controversies surrounding how the public understand mental illness have corollaries in debates surrounding how scientists conceptualize mental illness,” writes Schnittker.

Yet clinicians themselves rarely agree on diagnoses. Schnittker points to one study where agreement among clinicians on thirty five separate cases amounted to only 46 percent on the category of the disorder and 20 percent on the specific diagnosis.

We also cannot look to the research on psychiatric disorders to provide much consensus.

“Results of one study could not easily be compared with another. A study could be promising but not easily reproduced in another setting,” writes Schnittker.

Psychiatric disorders are, after all, human disorders.

Robert Spitzer, who led the task force that wrote the DSM-III was tasked with writing a manual that accurately reflected psychiatric diagnosis as they may appear in varied and nuanced forms in a wide variety of people. He also had to do so without displaying any bias toward any one theoretical orientation, be both sensitive and specific, and base diagnoses on their symptoms while still allowing them to be classified into categories.

The result of the DSM-III, however, characterizes the problem that diagnosing and classifying mental disorders may always face: it solved one problem while introducing many more.

“Once the problem of reliability had been addressed, researchers were in a position to question the validity of psychiatric disorders using better evidence – and indeed, evidence that could not be provided before the development of the specific criteria,” writes Schnittker.

As the process goes, there will always also be proposals for revisions to better improve the DSM and perhaps satisfy individual interests. However, Schnittker points to Allen Francis, the architect of the DSM-IV, who conceded that there was likely no way to articulate a thoroughly satisfying definition of a mental disorder, even if there were ways to create useful diagnostic criteria.

Francis even went further to argue that in reality there might be no way to even define the concept of mental disorder.

What we can embrace, and what Schnittker suggests, is a dimensional approach.

“In a dimensional framework, psychological functioning is assessed on a spectrum. Individuals suffer, for example, from more or less depression, anxiety, and phobia. The dimensional approach assigns more significance to individual symptoms than entire syndromes,” writes Schnittker.

While the DSM may induce reification – the transforming of the abstract into the real – it might also obscure, and perhaps falsely create disorders out of what would be better left transparent.

“Clinical utility – always a goal of the DSM – is not well served by categorical thinking,” Schnittker writes.

One example is the diagnosis of schizophrenia. While the hallmark of the disorder is positive symptoms, clinicians have long noticed many other symptoms, such as cognitive deficits and poor working memory that occur as part of the disorder.

However, pharmaceutical research has been tailored to the symptoms explicitly listed in the DSM, and only those symptoms, which leads “to a discontinuity between the schizophrenia that is the subject of research and the schizophrenia that is the target of treatment,” according to Schnittker.

While scientists use the DSM to set the foundation for research on psychiatric disorders, the public seek insights to shed light on their experiences, and clinicians seek a way to effectively communicate and represent their work to other clinicians and outside parties. Schnittker points out that the DSM will continue to remain controversial because it is difficult – if not impossible – to envision a criteria that would satisfy every stakeholder.

In a well-written critique of the process of understanding and diagnosing psychiatric disorders, Schnittker exposes the many competing constituencies that complicate the development of the DSM. However, Schittker also encourages us to think beyond the polemic approach, to see that while a perfect agreement of psychiatric disorders may never be found, the strength of the mental health profession is its adaptive approach.

The Diagnostic System: Why The Classification Of Psychiatric Disorders Is Necessary, Difficult, And Never Settled

Jason Schnittker

Columbia University Press

August 2017

Hardcover, 305 Pages

Book Review: The Diagnostic System

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Claire Nana

Claire Nana is a regular contributor and book reviewer for Psych Central.

APA Reference
Nana, C. (2017). Book Review: The Diagnostic System. Psych Central. Retrieved on November 26, 2020, from
Scientifically Reviewed
Last updated: 30 Dec 2017
Last reviewed: By a member of our scientific advisory board on 30 Dec 2017
Published on Psych All rights reserved.