Secrecy and Made-Up Illnesses: The Latest Fight over Psychiatric Diagnosis

Psychiatrists are having one of their periodic dust-ups [2] over the question of diagnosis. The back-and-forth has to do with the development, by the American Psychiatric Association, of a new diagnostic bible, DSM-V, the manual that will determine how mental health professionals in this country divide wellness from disorder and, in the disorder category, one condition from another. The updating is always controversial. Outright opponents of psychiatry find any change suspect: How is it that a person might be judged ill in one era and healthy in another?

In this case, the critics, Allen Frances [3] and Robert Spitzer [4], are psychiatrists who have been responsible for just that sort of shift. They led, respectively, the task forces that developed the two prior diagnostic and statistical manuals, DSM-IV and DSM-III. In effect, the old guard says that the new undertaking is too secretive—scholars reshaping the DSM categories have signed nondisclosure commitments, a highly unusual step in the academic world, where the science of diagnosis resides. The critics also claim that the time is not ripe, that research results do not yet justify the adoption of a new framework for classifying mental illnesses.

For the record, I think the APA’s attempt to keep the decision-making process secret is indefensible. The other matter, whether the diagnostic system needs and is ready for revision, is extraordinarily complex. DSM-IV appeared in 1994; the fifth edition is expected in 2012. The interval is long enough for a good deal of research to have been generated and also stable enough, in terms of the way we treat most patients, that any paradigm shift should be suspect. We want our practices to reflect important new findings about the nature of mental disorders, but we don’t want psychiatry to lurch around—and especially not when social issues seem to be at stake, like the boundary between hyperactivity and boyishness, social anxiety and shyness, sadness and depression.

What hasn’t yet surfaced in the current debate is acknowledgment of a fundamental change in the way that informed psychiatrists see the project of outlining and justifying diagnoses. Psychiatry has, by and large, dropped the illusion that its diagnoses are what philosophers call “natural kinds.” A natural kind is something that simply exists in nature. A mental disorder that arises from a simple gene defect (think of Down syndrome) is close to being a natural kind: When you name the genetic difference, you imply a good deal about what may be disabling in the person. But even this example is flawed—some people with the syndrome function well—and most mental illnesses are yet farther from any diagnostic ideal.

In past manuals, when psychiatrists said that schizophrenia [5] was characterized by typical symptoms (delusions, hallucinations, loss of motivation) and prolonged social and occupational dysfunction, they were trying to distinguish patients who shared a common disease that exists in nature. How schizophrenia arose and persisted was unknown—perhaps through common genetics or brain pathway disruption. Still, the idea was that by specifying manifestations of dysfunction and testing the results (does the disease run in families, lead to predictable bad outcomes, respond to given treatments?), the profession would get ever closer to a natural phenomenon, a disease state like pneumococcal pneumonia. One of the standing metaphors in the field—sometimes used more as a joke, sometimes less—had to do with the search for the “schizococcus,” a fictional bacterium, which (depending on the era) might stand in for one or another cause that would explain schizophrenia and determine once and for all which of the diagnostic criteria had been helpful and which had been misleading. The key metaphor here is “carving nature at the joints.”

But recent research results suggest that even for a near-universally accepted disorder like schizophrenia, a unifying cause will prove illusory. The genetic underpinnings of schizophrenia [6] look ever more complicated. Mutations occurring in a single pregnancy can give rise to a marked vulnerability for the illness. Those mutations occur in different places in the child’s genome; they may not involve abnormal genes but rather “repeats” of genes that function well when a person has fewer copies of them. No one gene or disordered brain pathway will “explain” the illness. The boundaries of schizophrenia, as it merges with personality disorders or with normal eccentricity, are unlikely to be sharp. And the situation is yet worse for more common, less dramatic conditions like anxiety disorders. In effect, the strange bird that is mental illness may have no joints.

Many psychiatrists have come to doubt that mental illnesses should be thought of as natural entities to be discovered. That shortcoming is not as dire as it first sounds. High blood pressure and asthma are legitimate diagnoses even though their causes are diverse, and reasonable observers disagree on the conditions’ lower limits. And good diagnoses have “predictive validity”: They suggest how disorders will progress, which symptoms they will produce, and which remedies will ameliorate them. When diagnoses fail such a test—when research shows that the labels are, in effect, bad hypotheses—they are thrown out of the manual. An example [7] is “involutional melancholia,” a new-onset anxious depression said to affect women at midlife; when it was shown that there was no postmenopausal peak for depression, and when it was found that the patients’ anxiety was a marker of past mental illness, IM was jettisoned in the transition from DSM-II to DSM-III.

For all its flaws we can’t do without diagnosis. Think of a patient who comes to a doctor after a series of panic attacks and is reassured: “You don’t have heart disease. You won’t die from these palpitations. We have ways to treat panic, with medication or psychotherapy.” Or think of a parent whose child has anorexia and learns that the condition is life threatening. In these situations, our difficulty bounding an entity and our fear that it lacks an “essence” are irrelevant. We need to be able to name the thing—panic disorder, anorexia—and convey what we know about it. Similar requirements exist for research. Schizophrenia in Verona must be schizophrenia in Boston. But these arguments are pragmatic, suggesting that diagnosis is a method (of grouping suffering people) that happens to be of use to clinicians, researchers, patients, and families.

A sentiment for something vaguely resembling the “natural kind” does persist in scholarly writing. My friend Kenneth Kendler, a psychiatric geneticist at Virginia Commonwealth University, and Ken’s colleague, Peter Zachar, a psychologist at Auburn University, have proposed [7] a thought experiment in which the historical clock is wound back 10,000 years, to the verge of the development of agriculture, and evolution is allowed to proceed—with this tape rewind performed repeatedly. Imagine that some human characteristics develop most of the time: pair bonding; communal living; success for people with high intelligence or astute empathy. How many contemporary diagnoses would appear regularly in these trial runs, as glitches arising in the course of building a complex brain that must then confront contradictory social demands? Kendler and Zachar do not answer the question, but schizophrenia, autism, major depression, and panic anxiety appear on their candidate list.

Still, increasingly, theorists argue that no curtain will ever lift and reveal a platonic ideal of schizophrenia (or asthma) and validate one set of diagnostic criteria while discrediting another. Much of biology is in the same bind. (For example, Zachar convincingly argues that the definition of species, of plants and animals, can never be conclusive.) But in psychiatry, this legitimate scientific dilemma seems especially consequential—and it is likely to lead to disputes in which any strong, fixed position is bound to be a bit misleading. Finally, no one knows how to weight the competing needs for stability of diagnosis and accuracy in the light of new research. The most thoughtful psychiatrists are likely to be like agnostic priests, believing in the centrality of the diagnostic enterprise while doubting that what it reaches for exists.