Schizophrenia, “just the facts” 4. Clinical features and conceptualization
Introduction
Although schizophrenia has been extensively studied and described as a disease entity for the past century, its precise clinical nature remains undefined. Since its demarcation and labeling as dementia praecox by Kraepelin (1919) and schizophrenia by Eugen Bleuler (1911), both its definitions and scope have varied (Nasrallah and Smelzer, 2003). It has been suggested that changing definitions of schizophrenia impede research into its nature as investigators keep chasing a moving target. Conversely, it has been argued that only a better understanding of schizophrenia can lead to its more precise definition. We have previously summarized a series of replicable and durable “facts” in schizophrenia (Tandon et al., 2008a). In this article, we elaborate the core clinical features of schizophrenia (Table 1) and discuss its diagnostic criteria. Since definition of a disorder and description of its nature are two aspects of an iterative process, we begin with a discussion of its evolving definitions leading up to current diagnostic criteria.
Section snippets
Evolution of the concept of schizophrenia from Kraepelin to DSM-IV-TR (Fig. 1)
Our present conceptualization of dementia praecox and schizophrenia derives principally from the work of Kraepelin (1919), Bleuler (1911) and Schneider (1959); differences in their ideas about the basic nature of this illness have caused discrepancies in its definition over the past century (Hoenig, 1983). Although case descriptions resembling schizophrenia go back a few millennia, its consideration as a disease entity dates back to the mid-19th century. Griesinger (1861) described what would
Clinical features of schizophrenia
Although there is no consensus about the essential criteria that must be met to make a definite diagnosis of schizophrenia, there is broad agreement about the general clinical features of the schizophrenic syndrome. Table 1 summarizes what we currently believe about the clinical expression of schizophrenia with varying degrees of confidence. We briefly discuss each of these clinical features [psychopathology, outcome, and course] and then explore its varied expression (heterogeneity).
Reconceptualizing schizophrenia
The authors propose that while it is premature to dump the very concept of schizophrenia, it is necessary to discard the current construct, disassemble its components, and reconstruct a more valid and meaningful entity.
Given the extreme heterogeneity across its clinical expression, as also its etiology and pathophysiology as discussed in previously published articles in this series (Keshavan et al., 2008; Tandon et al., 2008b), some have suggested that it is time to completely abandon the
In conclusion
The clinical characterization of schizophrenia is marked by several paradoxes. It is very unlikely to be a unitary disease entity and yet it appears to be one of the best validated psychiatric diagnoses. Despite the absence of pathognomonic clinical features or specific laboratory tests, it has high inter-rater diagnostic reliability and universally accepted broad prognostic and treatment implications. We know enough about the present construct of schizophrenia to recognize that it may be a
Role of funding source
Independently prepared by authors. No external funding.
Contributors
Contributors to research and writing of manuscript. Rajiv Tandon, Henry Nasrallah, and Matcheri Keshavan.
Conflict of interest
This statement was independently developed by Rajiv Tandon, Matcheri S. Keshavan, and Henry A. Nasrallah.
Acknowledgements
We acknowledge the tens of thousands of patients who have taught us what really matters in schizophrenia and our clinical and research colleagues who continually help us sharpen our thinking about its essential nature.
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