Original articleOne single diagnosis, bodily distress syndrome, succeeded to capture 10 diagnostic categories of functional somatic syndromes and somatoform disorders
Introduction
Physical complaints not attributable to verifiable, conventionally defined diseases, i.e., functional somatic symptoms, are prevalent in all medical settings, but their classification is contested as numerous overlapping diagnoses and syndrome labels exist [1]. Each medical specialty seems to have its own diagnostic label [2]. Psychiatry uses the designation somatoform disorders, while medical specialties prefer diagnoses like chronic fatigue syndrome (CFS), fibromyalgia, irritable bowel syndrome (IBS), chronic benign pain syndrome or multiple chemical sensitivity (MCS) [2], [3]. These diagnoses are referred to as functional somatic syndromes. There is, however, substantial evidence now that the various functional somatic syndromes are not clearly distinct disease entities [2], [4], [5], [6], [7], but rather represent a common phenomenon [8], [9], [10] with different subtypes [11], [12], [13]. Similarities have been documented as regards diagnostic criteria [4], etiology [5], pathophysiology [10], [14], neurobiology [15], [16], [17], psychological mechanisms [18], patient characteristics [2], [3], and treatment response [19]. The current fragmented approach to functional somatic symptoms due to the various syndrome diagnoses is an obstacle for research and a hindrance for effective patient care.
Recently, bodily distress syndrome was introduced as an empirically based diagnosis that may help solve the problem of diagnostic confusion [12]. In contrast to the diagnoses of functional somatic syndromes and the somatoform disorders that have been developed on the basis of highly selected patient populations or just by consensus, the bodily distress syndrome diagnosis is based on a large representative sample of patients recruited from primary care, a neurological and an internal medical setting [12]. The patients were assessed by trained physicians for any physical symptoms and not only for symptoms belonging to a predefined (specialty-specific) symptom list. Furthermore, we applied an exploratory statistical approach that explores the relationship of the symptoms to each other without any presumption regarding symptom clusters. This is in contrast to the confirmatory approach that is very popular in classification research, but which can only confirm a predefined symptom structure. Although functional somatic symptoms form a continuum from few to many symptoms without clear “cut-off” to define the boundary of illness, one distinct bodily distress syndrome could be identified. Bodily distress syndrome could be divided into a severe, multiorgan type and a modest, single-organ type with symptoms primarily from one organ system. The single-organ type was further divided into four subtypes; a cardiopulmonary (CP), a gastrointestinal (GI), a musculoskeletal (MS) and a general symptoms (GS) type (Fig. 1). Since these symptom profiles are in line with various other studies [13], [20], the finding of bodily distress syndrome subtypes seems to be quite robust.
We have previously hypothesized that bodily distress syndrome may replace most of the existing diagnostic categories of functional somatic syndromes and those of the somatoform disorders that are characterized by physical symptoms [21] (Fig. 1). This would be preferable to the approach proposed by the DSM-V workgroup on somatic symptom disorders which would entail two diagnoses: a “psychiatric” diagnosis on Axis I of “complex somatic symptom disorder” together with a “medical” diagnosis of a functional somatic syndrome on Axis III [22]. We believe that this proposed dual diagnosis solution would be a step backward in terms of attempting to unify the efforts of functional somatic syndrome research and to resolve the current dualistic diagnostic approach [23]. Very few previous studies have examined the overlap of the categories of the functional somatic syndromes and somatoform disorders, and no study to date has examined the unifying bodily distress syndrome approach against current diagnostic categories.
In the current study, we aimed to test whether (1) patients fulfilling criteria for six different functional somatic syndromes and four different somatoform disorders were diagnosed by the new construct of bodily distress syndrome, (2) symptom profiles were comparable between specific functional somatic syndromes and their corresponding bodily distress syndrome subtypes, and (3) comorbidity rates with anxiety and depression differed between “medical” functional somatic syndromes, “psychiatric” somatoform disorders and the unifying bodily distress syndrome diagnosis.
Section snippets
Methods
This study is a secondary analysis of three representative samples of patients from primary care (n=1785), internal medicine (n=294) and neurology (n=198). A detailed description of the included samples and study procedures can be found in [12]. We therefore provide only a short overview of how the data on functional symptoms were obtained.
Results
Table 1 shows that all the patients except one reaching criteria for Fibromyalgia, CFS, IBS, or hyperventilation syndrome as defined by our diagnostic algorithms also fulfilled diagnostic criteria for Bodily distress syndrome. Among the patients diagnosed with any of the DSM-IV somatoform disorders presenting with physical symptoms, 89.9% qualified for the bodily distress syndrome diagnosis. For the remaining functional somatic syndromes explored, this was the case in between 93.8% and 95.3% of
Discussion
In this secondary analysis of a large epidemiological study, the proposed diagnostic concept of bodily distress syndrome included nearly all patients who fulfilled criteria for one of six functional somatic syndromes as defined by our diagnostic algorithms, or for one of the DSM-IV somatoform disorders characterized by physical symptoms. Furthermore, the subcategories of bodily distress syndrome single-organ type seemed to be supported by their close relationship with the corresponding
Conclusion
The empirically established bodily distress syndrome diagnosis covered the whole range of functional somatic syndromes and somatoform disorders explored in this study and may have the potential to replace numerous overlapping diagnostic labels and to reduce the diagnostic confusion that currently prevails in the field of functional somatic syndromes. The bodily distress syndrome concept offers a common language and ground for the understanding of functional somatic symptoms. This may open up
Acknowledgments
The study was funded by a grant from the Danish Medical Research Council (grant number 9801278 and 9601898), the Health Service of Aarhus County (project number 0871), the Hede Nielsen Foundation, the fund “Puljen til Styrkelse af Psykiatrisk Forskning” and Biomed1 grant BMHI-CT93-1180.
We wish to thank the participating patients, the physicians and their secretaries and the interviewers.
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