Psychiatric Diagnosis 2.0: The Myth of the Symptom Checklist

This article is co-authored by Ronald W. Pies, M.D., clinical professor of psychiatry at Tufts University Medical School and professor emeritus of psychiatry at the State University of New York Upstate Medical University; and Mark L. Ruffalo, D.Psa., L.C.S.W., a psychoanalyst and instructor of medical education (psychiatry) at the University of Central Florida College of Medicine.

Following the publication of our last post, “What Is Meant by a Psychiatric Diagnosis?”, we received feedback from a few individuals raising questions and counterarguments to our assertion that psychiatric disorders—as described by their DSM diagnostic categories—can accurately be said to cause symptoms. We wish here to clarify and expand on the points made in our original piece.

Our position, roughly speaking, could be summed up in three basic principles: 1. Avoid definitional essentialism. 2. Embrace clinical pragmatism. 3. Respect ordinary language.

In turn, these principles lead us to three fundamental conclusions, which we flesh out in our original article and further elucidate here:

1. There is no "essential definition" (i.e., one specifying necessary and sufficient conditions) for terms like "disease", though entities called by this name typically possess "family resemblances."

2. The most clinically relevant family resemblance among members of the class called "disease entities" is the presence of prolonged or substantial suffering (or distress) and incapacity (or impairment); and these issues constitute the central focus of clinical care and treatment.

3. The concept of "cause" and "causality" is complex—and, like "disease", admits of no essential definition. Nevertheless, it is quite consistent with ordinary language to say that at least some psychiatric disorders—denoted by their respective DSM diagnostic categories—represent causes of a patient's suffering and incapacity in the mental, psychological, and behavioral realm (see Parker-Ryan, n.d.)

Any one of these principles or conclusions would merit a long paper, which would be far outside the bounds of a blog. Nevertheless, we can "unpack" our three principle conclusions and elaborate on some additional points that have been raised in response to our article.

The Definition of Disease

The concept of "disease"—its meaning, scope, definition, diagnosis, and treatment—has been a source of controversy since the ancient Greek academies of Knidos and Kos competed with one another (Turgut, 2011). We are not surprised the controversy continues to this day! Although some scholars proffer definitional distinctions among terms like "disease", "disorder", "illness", "malady", "morbus", etc., these terms are actually used very loosely—if not promiscuously—in the medical literature, and in everyday medical practice (Pies, 2009).

The commonly made binary distinction between "disease" (known pathophysiology) and "disorder" (unknown cause or pathophysiology) is of very limited clinical utility. For example: Kawasaki disease is an inflammatory condition affecting children, whose cause/etiology remains unknown. But it is not called "Kawasaki disorder" on that basis. More importantly, many medical conditions do not lend themselves to the binary distinction between disease and disorder, given that knowledge of etiology and pathophysiology exists on a broad continuum.

Suffering, Incapacity, and the Clinical Reality

Very few physicians contemplate their overcrowded waiting room and think to themselves, "Hmmm…I wonder which of these patients has a disease, and which has a syndrome, a disorder, a malady, or an illness?" The physician's chief concern is with determining who is experiencing suffering and incapacity (in varying proportions); identifying a likely cause, whenever possible (it often isn't!); and relieving the patient's misery safely and effectively.

Following the lead of the late psychiatrist Robert Kendell (1975), we believe that suffering and incapacity are the main elements of the disease concept. The physician (and non-medical psychotherapist) are thus most concerned with the alleviation of suffering and incapacity, regardless of whether we classify the patient's presenting problem as a disease, a disorder, or an illness.

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The Meaning of "Cause"

As psychiatrist Awais Aftab (2020b) suggested in his response to our article, the term "cause" is used in various ways, depending on the context. And, as the philosopher Ludwig Wittgenstein would remind us, the "meaning" of a word depends critically on how it is used, and for what purpose (Biletzki, 2018).

We would distinguish at least three senses and contexts for the term "cause": etiopathological causation, clinical causation, and causation in ordinary language.

Etiopathological Causation
This refers, ultimately, to the physical and physico-chemical mechanisms through which a disease process develops; e.g., the role of the tuberculosis bacillus in causing tuberculosis. In many ways, this is the "gold standard" to which medical science aspires, but which is often unrealized, particularly in psychiatric (and some neurological) disease entities.

Clinical Causation
This refers to the clinician's identification of a "best fit" between the patient's presenting signs and symptoms, and a recognized clinical entity; i.e., the patient's signs and symptoms "map onto" a particular syndrome, disease, disorder, etc., and—importantly—not to some alternative condition. In the philosophy of science, this type of determination is sometimes called "inference to the best explanation" (Willis, Beebee, & Lasserson, 2013).

The condition so identified may or may not be understood etiopathologically. Indeed, while etiopathologic diagnosis is usually the goal in medical diagnosis, there remain many conditions called "idiopathic" in general medicine; i.e., "We don't know what causes this." A good example is idiopathic facial paralysis (IFP) sometimes called Bell Palsy, for which there are many possible explanations, but no clear etiology. Nevertheless, note that physicians routinely cite IFP as "the most common cause of unilateral facial paralysis" (Taylor, 2019, emphasis added). Here we see an example of how a disorder without a known cause can itself be considered the cause of the patient's problem.

Another example: Let's say the patient presents with severe, unilateral head pain accompanied by nausea and extreme sensitivity to light. The patient asks the physician, "What's causing my problem, Doc?" The physician—having performed a careful neurological exam and ruled out, e.g., a brain tumor—replies, "I believe you are having migraine headaches." Interestingly, the word "migraine" is probably a corruption of the Latin, hemicranium, meaning, "half the skull". The etiopathology of migraine—though much clearer now than 100 years ago—is still not well or completely understood; i.e., "The exact cause of migraines is unknown…" (National Health Service, 2019).

Now, a "wiseass" (or very clever) patient might retort, "So all you’re telling me, Doc, is that my one-sided headaches are caused by pain on one side of my head!" Of course, there is much more to the neurologist's understanding of migraine—e.g., what triggers it; its course and prognosis; genetic factors that make it more likely, how it responds to treatment, etc. These factors represent some of the "external validators" that help define disease categories. The same type of validation applies to most of the major DSM diagnoses; e.g., schizophrenia, bipolar disorder, major depression, and yes—even generalized anxiety disorder (see, e.g., Anxiety Institute, 2020).

Causation in Ordinary Language
Dr. Aftab (2020b) explicitly takes up this meaning of "cause" in his response, i.e., he notes that, "In ordinary language, we sometimes use 'cause' … as [meaning] something along the lines of 'this is how to best make sense of it.'"

So, when we ask, "What was the cause of Smith's panic attack?" it is perfectly understandable to reply, in ordinary language, "It turns out Smith has panic disorder." This claim, of course, doesn't address the etiopathology of panic disorder. Nor does it imply that other, perhaps subsidiary or contributing causes can't be posited or discerned; e.g., "Smith was under a lot of pressure at work," or "Smith had just been evicted from his apartment." We may even go so far as to posit unconscious causes that would lend themselves to a psychoanalytic understanding of panic disorder.

But none of these additional causes impugns—or renders in any sense tautological—our "ordinary language" claim that Smith's problem is due to, caused by, or a consequence of his having panic disorder. That is, to use Aftab's formulation: his problem is "best made sense of" by this diagnosis.

The Diagnostic Criteria Are Not the Disorder

In considering these philosophical matters surrounding psychiatric diagnosis, we are reminded of a Buddhist saying that may be helpful in clarifying the difference between a DSM criteria set and the disorder it "points" to:

A finger pointing at the moon is not the moon.

The idea being: the DSM criteria set of symptoms and signs doesn't "cause" anything, since the criteria are just printed words on a page. But they point to something "real" outside themselves—and that entity, whatever its ultimate nature, does have what might be called "causal potency" or "causal efficacy", i.e., it causes the symptoms and signs, as well as the suffering and incapacity.

For example, in making a diagnosis of major depressive disorder, we may use the DSM criteria set to aid in establishing a diagnosis, but the criteria set in DSM is not the disorder! The criteria refer to the disorder that exists as a real entity—a condition or "state of affairs"—outside of the DSM. In short, it is not the DSM criteria set that "causes" symptoms, but the disease or disorder to which it refers that does so. The DSM-5 itself makes this clear. It states that the diagnostic criteria sets

…summarize characteristic syndromes of signs and symptoms that point to an underlying disorder with a characteristic developmental history; biological and environmental risk factors; neuropsychological and physiological correlates; and typical clinical course (American Psychiatric Association, p. 19, emphasis added).

These features of the disorder make up what we earlier called "external validators" for the disease category (see Ruffalo & Pies, 2020). They help point to what Dr. Aftab (2020b) calls "some underlying causal structure" that lends explanatory power to the diagnosis. For example, many psychiatric diagnoses demonstrate predictive validity—basically, predicting what will likely happen down the road. Contrary to some claims, predictive validity does not entail tautological confirmation, such as when someone with schizophrenia—for which hallucinations are one of the diagnostic criteria—is found, unsurprisingly, to have hallucinations two or three years after diagnosis. A diagnosis of schizophrenia also predicts, for example, a higher than expected likelihood of a dementia diagnosis, up to ten years later, even though dementia is not part of the diagnostic criteria for schizophrenia (see, e.g., Ahearn et al., 2020).

The Symptom Checklist Myth and the Case Formulation

Critics of psychiatric diagnosis often claim that "All you psychiatrists do is check off a bunch of symptoms, and bingo!—that's how you diagnose the patient!" This is not only false, it is dangerously misleading. It implies that the clinician has no responsibility beyond matching the patient's complaints ("I can't sleep…I'm feeling down in the dumps…" etc.) to a list of symptoms in the DSM. This totally misunderstands the process of medical-psychiatric diagnosis.

The word "diagnosis" is derived from the Greek dia- (between) and gnosis (knowledge). Thus, diagnosis entails knowing the difference between one condition and another. That is how clinicians are able to exclude dozens of possible "culprits" and settle on one or two. As Dr. Aftab (2020a) notes in his initial blog, "…to say 'Your anxiety is caused by generalized anxiety disorder' can be interpreted as, 'The way I understand your anxiety, it seems to be best described as 'generalized anxiety disorder' rather than 'major depressive disorder with anxious features', or as 'panic disorder'."

The "rule outs" also include a host of medical and neurological disorders that can mimic psychiatric conditions (see, e.g., McKee & Braum, 2016). Indeed, the DSM-5 itself makes it crystal clear that simply checking off symptoms cannot and does not constitute a psychiatric diagnosis—which requires a comprehensive case formulation:

The case formulation for any given patient must involve a careful clinical history and concise summary of the social, psychological and biological factors that may have contributed to developing a given mental disorder. Hence, it is not sufficient to simply check off the symptoms of the diagnostic criteria to make a mental disorder diagnosis (American Psychiatric Association, p. 19, emphasis added).

Conclusion

Causation in the clinical sense, and causation in ordinary language, nicely coalesce in this statement from the Anxiety Institute (2020), which also happens to summarize our concept of "disease":

Generalized Anxiety Disorder causes its sufferers great distress and trouble functioning in several different areas, such as school, work, at home with family, or in social contexts with friends [italics added].

We maintain that it is both philosophically and scientifically valid to state, for instance, that a patient's persistent worry, indecisiveness, and insomnia are caused by their generalized anxiety disorder; and that a diagnosis of generalized anxiety disorder (or major depressive disorder, bipolar disorder, etc.) does not merely re-package and re-state the patient's symptoms; but rather, points to a "real-world" disease entity. Many theories may be posited about what causes the disorder, but we can reasonably say that it is the disorder itself that causes the patient's signs, symptoms, suffering, and incapacity.