IJE Advance Access originally published online on March 1, 2006
International Journal of Epidemiology 2006 35(2):477-478; doi:10.1093/ije/dyl035
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Commentary |
Commentary: Symptoms not associated with disease: an unmet public health challenge
1 Department of Psychological Medicine and Symptoms Research, School of Molecular and Clinical Medicine, University of Edinburgh, UK
2 Department of Psychological Medicine, Guy's, King's and St Thomas' School of Medicine, London, UK
* Corresponding author. Kennedy Tower, Royal Edinburgh Hospital, Edinburgh, EH10 5HF, Scotland, UK. E-mail: jane.walker{at}ed.ac.uk
Accepted 9 February 2006
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Medically unexplained symptoms |
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 Top Medically unexplained symptoms Why are medically unexplained...Which diagnosis?New evidenceReferences |
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Modern medicine is based on pathological diagnosis. But many patients present with symptoms that lack any identifiable pathology. How should their ‘medically unexplained’ complaints be understood and categorized so as to provide an understanding of their condition and guide their care? Within psychiatry medically unexplained symptoms have been classified under the somatoform disorder label. Medical specialties have also played a part in naming symptoms-based syndromes, leading to a number of specialist-based diagnoses, for example, irritable bowel syndrome (gastroenterology), non-cardiac chest pain (cardiology), and chronic pelvic pain (gynaecology). Should we be interested in these syndromes and are these syndrome-based diagnoses the most accurate and useful way to conceptualize them?
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Why are medically unexplained symptoms important? |
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TopMedically unexplained symptomsWhy are medically unexplained...Which diagnosis?New evidenceReferences |
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The problem of medically unexplained symptoms is a big one. Recent studies have shown that approximately one-third of new patient attenders at hospital outpatient clinics describe symptoms that specialists classify as only ‘somewhat’ or ‘not at all’ explained by organic disease.1 Medically unexplained symptoms are also an important cause of chronic illness and healthcare utilization. Carson et al.2 found that 8 months after their neurology consultation half the patients with unexplained symptoms described their symptoms as the same or worse. Reid et al.3 found that, at 3 year follow-up, patients who presented repeatedly with medically unexplained symptoms continued to have high levels of functional disability and high use of health services. But despite its size and importance the problem continues to be neglected.
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Which diagnosis? |
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TopMedically unexplained symptomsWhy are medically unexplained...Which diagnosis?New evidenceReferences |
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The failure to adequately address the problem of medically unexplained symptoms is in part due to the lack of accepted diagnoses. Traditionally medicine has classified symptoms, and therefore patients, into diagnostic categories, based on presenting symptoms and the underlying disease or pathology assumed to be causal. However, medically unexplained symptoms by definition do not fit into this system. One approach is to treat them as if there is organ system pathology and to give ‘medical’ diagnoses such as ‘irritable bowel syndrome’ and ‘fibromyalgia’. Another is to assume that they represent the physical presentation of a psychological or psychiatric illness, in the form of ‘somatoform disorder’ (mental illness in somatic form). This latter approach takes little heed of bodily systems but categorizes by symptom type and number.
The classification of medically unexplained symptoms as one syndrome or many discrete syndromes has been debated widely. White4 has suggested that using a number of discrete syndrome diagnoses is more helpful in understanding aetiology and improving treatments than considering them as one. However, the division of medically unexplained symptoms into specific syndromes suggests that these are independent diagnoses, each with its own characteristic risk factors, causes, and presenting symptoms. The alternative is that these are not considered separate diagnoses but rather variations of a general functional somatic syndrome, which might be subdivided using a dimensional classification.
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New evidence |
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TopMedically unexplained symptomsWhy are medically unexplained...Which diagnosis?New evidenceReferences |
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Aggarwal et al.5 have addressed the question of the nature of functional syndromes by studying the general population registered with a GP, rather than only those patients who have attended a medical practitioner. This approach has the potential to lead us to a better understanding of the prevalence of such symptoms unbiased by consulting behaviour. It also removes the inherent difficulties, in reporting and classification, which occur once patients have consulted regarding their symptoms and have been referred to a clinic specializing in a bodily system. They found that approximately one-third of their sample report symptoms fulfilling criteria for at least one medically unexplained syndrome. The fact that their sample is reasonably representative of the British population has important implications for our healthcare services.
They also found that patients experiencing one medically unexplained syndrome are significantly more likely to meet diagnostic criteria for another during the same time period and that these syndromes have a number of associated non-symptom factors in common; female gender, high levels of health anxiety, increased symptom reporting and increased reporting of recent adverse life events. These findings support the findings of previous studies showing substantial overlap in the symptoms said to be diagnostic of a number of medically unexplained syndromes6 and have suggested that patients who fulfil the diagnostic criteria for one unexplained syndrome meet criteria for another more commonly than would be expected by chance.7
Despite their current classification as discrete diagnoses, this study supports the argument that these syndromes have a great deal in common and suggests that the classification of medically unexplained symptoms into separate functional syndromes remains questionable. Furthermore if patients experiencing one medically unexplained syndrome are significantly more likely to experience another then our current classification system and medical-system-based management of these patients must change. Using our current classification system such patients will continue to be referred to multiple specialist clinics or will be left with unmanaged symptoms because these symptoms do not ‘fit’ into the syndrome they have been assigned. The increasing trend away from the central role of the general physician and towards further medical specialization will surely compound this problem.
This study confirms that patients presenting with symptoms suggestive of a medically unexplained syndrome should be also asked about others. Above all this paper reminds us of the value of primary care research in highlighting the shortcomings of categorizing patients to fit with medical specialization.
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References |
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TopMedically unexplained symptomsWhy are medically unexplained...Which diagnosis?New evidenceReferences |
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1 Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics. J Neurol Neurosurg Psychiatry 2000;68:207–10.
2 Carson AJ, Best S, Postma K, Stone J, Warlow C, Sharpe M. The outcome of neurology patients with medically unexplained symptoms: a prospective cohort study. J Neurol Neurosurg Psychiatr 2003;74:897–900.
3 Reid S, Crayford T, Patel A, Wessely S, Hotopf M. Frequent attenders in secondary care: a 3-year follow-up study of patients with medically unexplained symptoms. Psychol Med 2003;33:519–24.[Medline]
4 Wessely S, White PD. There is only one functional syndrome. Br J Psychiatry 2004;185:95–96.
5 Aggarwal VR, McBeth J, Zakrewska JM, Lunt M, Macfarlane GJ. The epidemiology of chronic syndromes that are frequently unexplained: do they have common associated factors? Int J Epidemiol 2006;35:468–76.
6 Wessely S, Nimnuan C, Sharpe M. Functional somatic syndromes: one or many? Lancet 1999;354:936–39.[CrossRef][ISI][Medline]
7 Nimnuan C, Rabe-Hesketh S, Wessely S, Hotopf M. How many functional somatic syndromes? J Psychosom Res 2001;51:549–57.[CrossRef][ISI][Medline]
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