Rather than showing "misclassification" early on, Bromet et al. really show how inadequate these concepts, especially schizophrenia, are for
early diagnosis and treatment. We need a model which links stage of
illness to treatment selection and allows people with a need for care (often months or years before the current diagnostic approach really makes sense) to receive the help they need. Our Clinical Staging Model is an attempt to work towards this (McGorry et al., 2006).
McGorry PD, Hickie IB, Yung AR, Pantelis C, Jackson HJ. 2006.
Clinical staging of psychiatric disorders: a heuristic framework for
choosing earlier, safer and more effective interventions. The
Australian and New Zealand Journal of Psychiatry 40(8): 616-622.
McGorry PD, Nelson B, Goldstone S, Yung R. 2010. Clinical staging:
a heuristic and practical strategy for new research and better health
and social outcomes for psychotic and related mood disorders. Canadian
Journal of Psychiatry 55(8): 486-497. View all comments by Patrick McGorry
We believe that the paper by Evelyn Bromet and colleagues will come to be viewed as a classic in psychiatric research. It addresses a fundamental problem that has long been recognized, but nevertheless is often overlooked in published papers, and sometimes in clinical practice and mental health service policies. One of the reasons that has made it easier to overlook this problem is that it has not been directly addressed with high-quality empirical data. This study changes that.
Briefly, the problem is that psychiatric diagnoses are often made based on the state of an individual at a given point in time. Yet we know that individual states change over time, and that longitudinal information (not always available) will generate a more valid diagnosis. As noted in their paper, this was recognized in the classic paper of Robins and Guze (1970), but it has also been emphasized by others since then. A paper by Robert Spitzer suggested that, while we have no “gold standard” in psychiatry, we could use a “LEAD” (“Longitudinal, Expert, and All Data”) standard, a central feature of...
Briefly, the problem is that psychiatric diagnoses are often made based on the state of an individual at a given point in time. Yet we know that individual states change over time, and that longitudinal information (not always available) will generate a more valid diagnosis. As noted in their paper, this was recognized in the classic paper of Robins and Guze (1970), but it has also been emphasized by others since then. A paper by Robert Spitzer suggested that, while we have no “gold standard” in psychiatry, we could use a “LEAD” (“Longitudinal, Expert, and All Data”) standard, a central feature of which was using longitudinal data to help verify diagnoses (Spitzer, 1983).
Dr. Bromet’s paper now reveals that, in a sample of individuals with psychoses, ascertained at first hospital admission, with carefully made diagnoses over several time points up to 10-year follow-up, the shifts in diagnosis were substantial. They were to some extent predictable, but not enough to warrant assuming the validity of a diagnosis based on evaluation at a single time point early in the course of the illness. Clearly, we can no longer afford to overlook the difference between diagnoses of psychotic disorders that are made based on cross-sectional versus longitudinal information. (Arguably a diagnosis of schizophrenia could be an exception to this rule, since individuals were very likely to retain this diagnosis if it had been made at the time of entry to the study.)
While these findings pertain to a treated sample in a high-income country (the U.S.), the implications are global, and there are a number of ways in which this question could be examined from other vantage points in non-Western settings. For example, consider a recent study of mental disorders in a representative community sample in China (Phillips et al., 2009). This study was large enough to ascertain many individuals with psychoses and (unusual for community surveys) used a clinician-administered interview to establish their diagnoses (SCID; Spitzer et al., 1992). Among the individuals diagnosed as having schizophrenia, about 25 percent were untreated, and another 25 percent had been minimally treated. This study did not follow individuals over time, but it illustrates the potential and importance of doing so for (previously) untreated samples identified in a non-Western setting (Ran et al., 2001). Examination of this group might provide a different perspective by which to study long-term diagnostic stability of psychotic disorders.
Spitzer, R.L. (1983). Psychiatric diagnosis: are clinicians still necessary? Comprehensive Psychiatry, 24, 399-411. Abstract
Phillips MR, Zhang J, Shi Q, et al. Prevalence, treatment, and associated disability of mental disorders in four provinces in China during 2001-05: an epidemiological survey. The Lancet. 2009;373(9680):2041-2053. Abstract
Spitzer RL, Williams JBW, Gibbon M, First MB. The Structured Clinical Interview for DSM-III-R (SCID) I: History, Rationale, and Description. Arch Gen Psychiatry. 1992;49(8):624-629. Abstract
Ran M et al. Natural course of schizophrenia: 2-year follow-up study in a rural Chinese community. The British Journal of Psychiatry. 2001;178(2):154-158. Abstract
This is an important and valuable piece of work. The attention to the reliability of ratings and diagnosis is well done, and achieving an 80 percent follow-up over 10 years in a U.S. sample is impressive indeed. I would be interested to know how they managed that. Documenting diagnostic consistency and shifts provides important data for our understanding of: 1) diagnostic processes and 2) the course of psychiatric disorder. I put “diagnostic processes” first because we have such an unscientific tendency to treat diagnoses like real “things,” as though we were talking about something like a Toyota Corolla, rather than as complex interactions occurring in social contexts. Questions crucial to the diagnostic process include, among other things, how and where the patient is seen, the training of the person giving the diagnosis, the diagnostic system in use, and (sometimes finally), the characteristics of the person being given the label. Although some of these concerns are impressively considered in this study, one important assumption discussed below is not.
Diagnoses are a...
Diagnoses are a crucial part of our field; they provide handy labels that can be useful for treatment, training and research. Or they can provide misleading reifications that indicate that something is “a disease” when in fact we know much less about that thing than having a diagnostic label would indicate. Knowing about changes and constancies in diagnoses may tell us about changes or lack thereof in patients. They may also tell us about implicit erroneous thinking in the person making the diagnosis. A joke among many consumers with severe psychiatric problems is that “They used to call me a schizophrenic, but when I got better they changed me to bipolar.” That could indicate that the person’s clinical state changed in a diagnostically relevant way, or it could indicate that the person making the diagnosis was influenced by the now disproved belief that people with schizophrenia never get better. The person making the diagnosis might assume that since this person improved, he or she must have been bipolar. That would be the changing of a diagnosis to fit a disproved belief of the person making the diagnosis. Or conversely, and one sees this on medical wards and even more in outpatient clinics, when a diagnosis is not changed, that might be because the person making the diagnosis is too harried (or heaven forfend, too lazy) to reevaluate the patient and that it’s just easier to write on the chart what has been written there before.
Another concern in the field of psychiatric diagnosis is the limits in our knowledge about the nature of psychiatric disorders, and here is where one major conclusion of this report is questionable. There are a lot of dicta these days running around as though they were definitive psychiatric truths, dicta like “psychiatric disorders are brain diseases” or “psychiatric illnesses are illnesses like any other." I am not here saying that these statements might not be true, but we really don’t know that they are or even exactly what they imply. As Robin Murray has noted, for example, the concept of “illnesses like any other” is rather bizarre since illnesses are not by any means all alike. Hypertension is too much of something, blood pressure, that at normal levels you'd better have if you want to be alive; pneumococcal pneumonia is entirely different; and, of course, a broken arm is different from both of these. In terms of a major conclusion of this report, the statement by Bromet et al. that “First-admission patients with psychotic disorders run the risk of being misclassified at early stages in the illness course,” may be seriously misleading. When a diagnosis changes, it could mean not that one or the other of the diagnoses was the correct one (and hence, that the disorders themselves don’t change, that you can only have one disorder and it’s just the question of getting it right), but it could mean that psychiatric disorders are not like that, that such a notion of disorder is incorrect, and that, on the contrary, one of our diagnostic types could fade into another over time. It is not rare, after all, if you know a patient over an extended period that you see what was an obsessional problem become a schizophrenic one or vice versa.
We don’t have to make either/or decisions about such possibilities—only recognize that our level of knowledge about psychiatric problems has serious limits. We can venture working hypotheses, which is better than assuming the truth of often implicit beliefs. Yes, diagnosis is very important, but it doesn’t necessarily mean that the diagnoses we have necessarily correspond to real unchanging things. The level of knowledge in psychiatry, as much as progress has been made, falls far short of allowing us to be sure we have the definitive story. Beware of nouns (such as diagnoses) in psychiatry! They may be indicating truths—or they may not. Very often, they reflect the best available working hypotheses about reality—no more and no less.
In my opinion, there are a lot of choices we do not have to make at this point in the trajectory of psychiatry. Specifically in regard to diagnosis, we do not have to decide whether or not to make a diagnosis, and then if we do, to treat it like a thing that couldn’t evolve into another thing. At this point, a psychiatric diagnosis is a helpful working hypothesis, not a definitive, all-revealing knowledge. I totally agree with the final conclusion of Bromet et al. for which their report provides important support: “Diagnosis should be reassessed at all follow-up points.” But I do not believe that their earlier conclusion is necessarily correct: that the first diagnosis can be a misclassification, and thus are implying that later diagnoses will identify the “real thing.” It seems highly likely to me that the disorders themselves can change, evolve, and resolve. We are not sure that a person with schizophrenia will always have schizophrenia. Is the last diagnosis always the “real” diagnosis, and are earlier different ones “misclassifications”? I don’t think we know that.
PRIMARY NEWSThe Shifting Diagnostic Sands of Psychosis