In psychiatry, we have a series of syndromes, such as depression. We call these disorders, because they make people miserable. They are associated with poor outcomes: up to and including, in the case of depression, suicide. The older clinical descriptions of the syndrome were rich, included subtleties, the associated slowing in thinking, a sense of unreality, and the anxiety that all so often distresses as much as the lowered mood. These are missing from the current DSM criteria.

And the author of DSM-IV thinks this is a mistake he and the other authors have made. For their brief criteria are seen by many as the disorder, rather than the simpler ways of saying, yes, this is the syndrome.

Why is it a bad idea to conflate our DSM criteria with the disorders themselves? Our historical review of symptoms of major depression presents three illustrative problems. First, for most diagnostic criteria, rapidity and reliability of assessment is critical. The developers of DSM-III explicitly preferred criteria that required low levels of inference, because these are typically more reliable (40). Many of the symptomatic criteria for major depression—such as changes in appetite, weight, psychomotor performance, and sleep—can be quickly and reliably assessed.

But some important features of psychiatric disorders may not be like that. They may be subtle, and time-consuming to evaluate. Does this mean that such symptoms should be disregarded? If DSM criteria for major depression constitute depression, that would be a logical conclusion.

But many of our classical textbook authors believed that derealization was an important clinical feature of major depression. We can understand why this did not make it into DSM: It is a subtle concept, time-consuming to evaluate, and perhaps of limited reliability. Yet, senior clinicians of earlier generations thought it was a critical feature of the depressive syndrome that reflected their patients’ lived experiences. Should we not evaluate it or teach it to our students because it is not in DSM?

Second, developers of diagnostic criteria are also appropriately concerned about specificity. A symptom could be quite clinically important, but if it is shared by many other syndromes, it would likely not make a good diagnostic criterion. Most of our textbook writers considered anxiety to be a prominent and clinically important part of the presentation of major depression. If we conflate our criteria with our disorders, we are then in the awkward position of suggesting that anxiety is not important in major depression because it is not in our criteria.

Third, to be practical, diagnostic criteria need to be succinct. For the key major depression criteria A1 and A7, DSM-5 lists three and two descriptors, respectively. As illustrated by our textbook writers, these lists are too short to capture adequately the range of human experience of the mood state of depression and the range of self-derogatory/pessimistic depressive cognitions.

One needs to go one step further. The disorder is not the experience. A syndrome is a pattern that is common to many: there are unique and specifically painful aspects for each person in each episode of depression. The clinical picture is not as in the textbook, nor is the experience. And if a clinician does not listen to that, then he or she should change careers. To public health or pathology.