The Diagnostic System

Why the Classification of Psychiatric Disorders Is Necessary, Difficult, and Never Settled

Jason Schnittker

• Publisher: Columbia University Press
• Year: 2017
• Topic: Psychology
• eBook ISBN:
  9780231544597
• Subtopic: Mental Health in Psychology
• Index: Psychology

Mental illness is many things at once: It is a natural phenomenon that is also shaped by society and culture. It is biological but also behavioral and social. Mental illness is a problem of both the brain and the mind, and this ambiguity presents a challenge for those who seek to accurately classify psychiatric disorders. The leading resource we have for doing so is the American Psychiatric Association's Diagnostic and Statistical Manual, but no edition of the manual has provided a decisive solution, and all have created controversy. In The Diagnostic System, the sociologist Jason Schnittker looks at the multiple actors involved in crafting the DSM and the many interests that the manual hopes to serve. Is the DSM the best tool for defining mental illness? Can we insure against a misleading approach?

Schnittker shows that the classification of psychiatric disorders is best understood within the context of a system that involves diverse parties with differing interests. The public wants a better understanding of personal suffering. Mental-health professionals seek reliable and treatable diagnostic categories. Scientists want definitions that correspond as closely as possible to nature. And all parties seek definitive insight into what they regard as the right target. Yet even the best classification system cannot satisfy all of these interests simultaneously. Progress toward an ideal is difficult, and revisions to diagnostic criteria often serve the interests of one group at the expense of another. Schnittker urges us to become comfortable with the socially constructed nature of categorization and accept that a perfect taxonomy of mental-health disorders will remain elusive. Decision making based on evolving though fluid understandings is not a weakness but an adaptive strength of the mental-health profession, even if it is not a solid foundation for scientific discovery or a reassuring framework for patients.

1

THE CONTESTED ONTOLOGY OF PSYCHIATRIC DISORDERS

The best place to start a discussion of psychiatric classification is with the people that psychiatric disorders affect directly. Consider two cases, both involving people at the boundary of formal classification. These cases are drawn from the American Psychiatric Association’s most recent volume of clinical cases, designed to help mental health professionals learn more about the latest edition of the Diagnostic and Statistical Manual.1 All of the cases in the volume are based on real people, though their identities have been disguised and their names changed. The cases are not necessarily typical of a disorder. Indeed, many were selected precisely to illustrate the ambiguities surrounding the manual’s criteria. They are, however, illustrative, especially for those who must struggle with implementing the criteria. The first is Olaf Hendricks, a fifty-one-year-old father.2 Olaf’s daughter lives overseas, and she recently had a baby. Olaf would like to visit his grandchild, but he is severely anxious about flying. His anxiety began three years ago when the plane he was on landed during an ice storm. He has flown since that incident, but on his last complete flight he cried during landing and takeoff. Subsequent to that, when Olaf was scheduled to fly to his daughter’s wedding, he ultimately refused to board the plane after arriving at the airport. His fear of flying affects more than his family life. It played a role, for instance, in his refusing to accept a promotion that would have involved significant travel. According to Olaf, his anxiety is limited to flying, though with some questioning his psychiatrist discovered that as a child Olaf feared being attacked by a wild animal. His earlier fear of animals was similar in its intensity to his current fear of flying, though it had dissipated because he now lives in a large city where encounters with wild animals are rare. According to the criteria in the Diagnostic and Statistical Manual, Olaf suffers from a specific situational phobia, in this case of flying. His disorder meets all the diagnostic criteria in the manual. It involves intense situational anxiety, it has caused significant distress, and it has caused significant functional impairment. In addition, Olaf also meets the diagnostic criteria for a specific phobia pertaining to animals, but, probably because he is unlikely to encounter wild animals in his current environment, that anxiety plays little obvious role in his life. The DSM permits this additional diagnosis, in part to allow for “significant impairment” that might be entirely unconscious; for example, Olaf might choose to live in a big city precisely to avoid wild animals. Olaf is not required to acknowledge or state this, however, for the psychiatrist to infer that it might matter.

The second case is Andrew Quinn, whose son recently died.3 His son had suffered from depression and substance abuse and, after a struggle, died of an apparent suicide. Andrew visited his psychiatrist two weeks after his son’s death, reporting that he felt life had lost its meaning. The psychiatrist continued to see him on a weekly basis in order to monitor his progress. His symptoms worsened over the next four weeks, with Andrew growing increasingly preoccupied with his son’s death and ruminating over what he might have done differently. Andrew also reported the other symptoms that compose a depressive episode, including sleeplessness, fatigue, sadness, feelings of worthlessness, and a loss of self-confidence. Although these symptoms are recent and form the reason for Andrew’s visit, there are other diagnostically relevant experiences in his history. Andrew had two prior episodes of depression, both occurring more than thirty years ago. According to the diagnostic criteria in the most recent DSM, Andrew is suffering from a major depressive episode. Although his symptoms are typical of grief and his son’s death happened less than two months prior—well within the timeframe in which we might ordinarily still expect some grieving—the DSM emphasizes how depression that begins in grief can eventually grow “autonomous” of that experience and thus be regarded as indicative of a deeper problem.4 Other features of Andrew’s situation are relevant to discerning whether this is a case of clinical depression and not just bereavement. In particular, the risk of depression following grief is presumed to be higher for Andrew given his history of depression.

What do these two cases reveal? At one level they reveal something simple: how matters of formal diagnosis hinge on seemingly slight matters. Andrew’s diagnosis hinges on what we regard as real depression and what we believe is an adequate time to grieve. Making a diagnosis also appears to depend on evidence of a preexisting risk, even if, as in Andrew’s case, that risk appeared many years ago. With almost exactly the same experiences and symptoms, a person without a history of depression might be regarded as simply bereaved, not depressed, especially this soon after a son’s death. Olaf’s case raises similar issues. In particular, for Olaf there are two sources of anxiety, even though he is concerned about only one. In this case, too, the past is critical. The DSM allows for a diagnosis based on what Olaf experienced in the past. According to the DSM, a disorder might still be present even when it has no apparent symptoms. In this way, the DSM assumes authority over and above what Olaf himself recognizes or appreciates. These two cases also point to the importance of professional judgment in addition to the words and rules of a text. A reliable diagnosis requires that the psychiatrist use the DSM faithfully. Yet a diagnosis also requires that the psychiatrist exert a considerable amount of judgment. In Andrew’s case, the psychiatrist must decide whether Andrew is really suffering from clinical depression, based on insights that probably stretch beyond the DSM. In particular, the psychiatrist must decide if the particular set of symptoms better describes grief or major depression, even though they are closely related. In Olaf’s case, the psychiatrist must probe further to learn about Olaf’s other fears, even if those fears have no obvious relationship with his current anxiety. What, though, compels a psychiatrist to use the DSM faithfully? And when presented with complex patients for whom a diagnosis requires reading between the lines, often based on issues that go well into a patient’s past, will all psychiatrists make the same determination? Regardless of the details provided in the DSM, psychiatrists are still left wrangling with the meaning of its text when presented with actual patients.

This book is concerned with the ambiguities surrounding psychiatric classification, of which these examples illustrate only a few. I hope these two cases illustrate something else, too. Much of my discussion will be abstract, in the sense that I will focus on the principles guiding the creation and revision of psychiatric nomenclature. Much of my discussion, too, will pertain to aggregate-level data, including prevalence rates, correlations, and population averages. It is my hope, though, that readers will always keep in mind that these issues, in the end, are not abstract; they are personal. They are not about lists of symptoms; they apply to people who are suffering. And debates regarding the best classification systems ultimately seek to impose some sort of significance (or insignificance) over the day-to-day experiences of individuals. The ambiguity surrounding psychiatric classification is not, however, a simple or self-evident matter. It is rooted in the deep ambiguity surrounding mental illness, one that is hard to clarify with even the most scientifically credible diagnostic criteria.

THE DEEP AMBIGUITY OF MENTAL ILLNESS

Many illnesses are foreign to the experience of the average person. Epilepsy is serious for those who suffer from it, but most people will never have a seizure. Minor jolts to the head happen periodically, but a traumatic brain injury is severe and has lasting consequences. The flu is seasonal and pervasive, but there are many other diseases that will never infect the average person. Some symptoms are simply remote to our experience, even if we occasionally experience a hint of what lies just beyond the border.

Many of the core symptoms of mental illness, however, are familiar to virtually everyone. Furthermore, in the case of mental illness, differences between the sick and well can appear only a matter of degree. Most people, for example, might not regard themselves as “depressed” in any significant way, but the feeling of being sad or unmotivated is hardly unusual. In fact, such feelings are routine features of everyday life. They are characterized by a wide variety of idiomatic expressions far removed from any medical connotations, as when we say we are feeling “blue” or “downhearted.” Similarly, most people might not panic in the face of something they fear, but virtually everyone can appreciate the unease of, for example, public speaking. At a minimum everyone can easily name those things they fear the most. And chances are your fears—whether of snakes, heights, or enclosed spaces—are shared by many other people. We might not even regard these experiences as symptoms at all and, instead, actively seek them out, as when people enjoy the pensive melancholy of music in a minor key.5

Perhaps there is a limit. Hallucinations might be regarded as the most severe kind of psychological symptom. Hearing voices when no one is around or seeing things that are not present represent especially bizarre experiences. And perhaps we can agree that such symptoms are the boundary, the point at which normal and abnormal part ways. Our commonsense view of the world allows only for externally generated auditory and visual cues. Yet even here the case is not so clear. Everyone appreciates the idea of a “delusion,” and the word is used frequently. But the term is more complex than is suggested by the ease with which people deploy it. “Delusion” implies beliefs that are incorrect, and assessing when thoughts are faulty is difficult. “You’re crazy” is an epithet, of course, but it is also an evaluation. It is an assessment of another person’s motives, beliefs, or rationality, and the term is often used indiscriminately. Furthermore, hallucinations are not entirely uncommon, suggesting that the frequency with which something occurs provides no guidance regarding its normality. Many people can appreciate the feeling of dislocation, for example, that comes from not getting enough sleep. Indeed, some studies find that more than a third of people experience hallucinations of some kind in their lifetime, even if most of those experiences are not associated with any specific psychiatric disorder.6 The symptoms of mental illness, then, are the “stuff of life.”

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. This, too, makes mental illness different from many other kinds of illness. The average person might have little sense about what causes epilepsy, for example, and so will seek the authority of an expert to diagnose it. Similarly, many people intuit that good and bad health “run in the family” and, thus, recognize the importance of genetic influences. Even so, people still leave the formal diagnosis of inherited conditions to professionals. For some things, like a broken bone, everyone understands the traumas that can cause it, but they still accept that the final determination of whether a bone is broken rests with an X-ray. For mental illness, the situation is quite different. The average person can easily appreciate the role of stress in feeling overwhelmed or maybe even depressed, without any sort of technological intermediary. The issue is not that such causes lack reality for being common. To the contrary, “everyday” causes gain credibility precisely because we appreciate how potent they are. The death of a loved one can produce profound sadness, one seemingly impervious to time and the support of friends. When individuals recognize themselves as suffering from depression they can almost always identify a precipitating cause and have little doubt about its significance. Science, too, has confirmed the reality of environmental causes of this sort, but the public has not waited for the insights of empirical research to draw its own conclusions.

Perhaps because the symptoms of mental illness are so common and explanations so easy to grasp, the concept of mental illness invites controversy. When everyone knows something about sadness—about what it feels like, about what causes it—claims of authority, even with respect to official diagnosis, can appear unnecessary or dubious. The public is quick to judge whether they think someone is “really” depressed, even as they withhold judgment about most other medical disorders. And when people are presented with so many potential causes of mental illness, the boundaries between what is or is not illness become porous. If sadness—even severe sadness—comes from living an ordinary life, how can depression ever be considered a disease? What sort of treatment could we deem absolutely necessary?

These debates are not merely matters of idle speculation. They have deep consequences. Parents struggle with whether to seek treatment for their misbehaving or underperforming children. Spouses struggle with the addictions of their partners. Policy makers struggle with how to provide health care to those who need it most. And psychiatrists struggle with crafting the most accurate diagnostic criteria. In the end, these concerns are concrete. The form of the question becomes personal: What causes my suffering? Do I have a problem, and, if so, what can I do about it? Questions of this sort are existential as much as medical. Formal diagnostic criteria are a different matter—the DSM provides some answers—but they have no less settled answers, and they, too, are at least partly a matter of philosophy.

CONTROVERSIES SURROUNDING FORMAL DIAGNOSTIC CRITERIA FOR PSYCHIATRIC DISORDERS

Formal diagnostic criteria for psychiatric disorders have existed for decades. They provide the “rules” for making professional diagnoses. They also provide the “catalogue” of relevant psychiatric symptoms. When applied correctly and consistently, formal diagnostic criteria are intended to produce a lingua franca for mental health professionals. They admit some experiences as symptoms but exclude others. They also provide thresholds and decision rules for adjudicating significance. This is what we regard as depression. These symptoms are significant. This is the point at which we say these symptoms reflect clinical depression rather than norma...

Table of contents

• Cover
• Title Page
• Copyright
• Contents
• Acknowledgments
• 1. The Contested Ontology of Psychiatric Disorders
• 2. What Diagnoses Are: DSM-III and the Form of Contemporary Psychiatric Diagnoses
• 3. DSM-III and the Descriptive Science of Psychiatric Disorders
• 4. Rethinking the DSM
• 5. How Professionals Use Diagnoses
• 6. How the Public Uses Diagnoses
• 7. How Scientists Use the DSM
• 8. How Cultures Use Diagnoses
• 9. The Contemporary Science of Psychiatric Nosology
• 10. The Endless Search for Validity
• 11. The Endurance of the Diagnostic System
• Notes
• Index