Department of Psychiatry, University College, Cork
Correspondence: GF Unit, Cork University Hospital, Wilton, Cork, Ireland. E-mail: t.dinan{at}ucc.ie
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INTRODUCTION |
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The group identified many areas of debate and disagreement within psychiatry and medicine, and in particular recognised that it is not a universal belief in the UK in 2003 that psychiatrists should indeed be responsible for the physical health of their patients. The aims of the group therefore were to produce a pragmatic and sensible consensus statement, which could be considered for use throughout the UK and Ireland. Most of the recommendations are evidence-based, but in areas where there is a lack of evidence a consensus opinion was formed. Since it is clear that we do not have answers to all of the questions, one of the main conclusions of the group was that large, prospective, long-term studies are urgently required.
Why has a consensus statement not been produced before? The answer to this question is probably that the data simply have not been available until now (Mohan et al, 1999). Dora Kohen points out that the issue has been the subject of much previous debate but such debate has not led to a conclusive outcome. Dixon et al (2000) showed clearly from the Patient Outcomes Research Team database that not only diabetes but very many other physical illnesses are undiagnosed in many of our patients.
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UNDIAGNOSED DISEASE |
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Within this cohort of people with undiagnosed glucose disorder is a significantly large group of individuals with psychiatric illness. There seems to have been an absence of awareness until recently that schizophrenia (and possibly bipolar disorder as well) could be considered as an independent risk factor for the development of diabetes (Ryan & Thakore, 2002). A recent BMJ series on all aspects of diabetes (epidemiology, diagnosis, management and complications) was notable for its absence of any mention of schizophrenia. Here indeed is a huge potential cohort of people with diabetes, and Bushe & Holt (2004, this supplement) stress the value of early diagnosis and treatment, which might lead to a reduction in the all-too-common deaths from cardiovascular events. We know that natural causes and not suicide explain the majority of the excess mortality associated with schizophrenia (Harris & Barraclough, 1998; Brown et al, 2000). We also know that diabetes is best considered a vascular illness, for which most patients routinely receive statins, angiotensin-converting enzyme inhibitors and aspirin in addition to their hypoglycaemic treatments. Furthermore, there appears to be reasonable evidence that diabetes can be prevented if those at greatest risk are targeted early enough and comply with their treatments (Knowler et al, 2002).
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HIERARCHICAL ASSESSMENT OF THE DATA |
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The prospective data examining the relationship between schizophrenia and diabetes began to emerge in 2003, and most of the data currently in the public domain have not yet undergone peer review. This body of data is reviewed by Bushe & Leonard (2004, this supplement), who conclude that the association between schizophrenia, antipsychotic medication and diabetes is largely based on less than optimal retrospective studies. The latter studies are reviewed in the paper by Haddad (2004, this supplement). A few studies have included a placebo group, and through these studies it emerges that we cannot necessarily blame antipsychotic medication when diabetes develops in an individual with schizophrenia. In the prospective studies that included both a placebo group and a requirement to actively and regularly measure blood glucose levels (as in randomised controlled trials performed to US Food and Drug Administration standards), we have learnt that the incidence of newly diagnosed diabetes does not appear to differ greatly between placebo groups and groups in which active drug comparators have been used.
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HOW DOES SCHIZOPHRENIA PREDISPOSE TO DIABETES? |
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ANSWERING THE DIFFICULT QUESTIONS |
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There is little doubt that some psychiatrists feel challenged by non-psychiatric illness and will feel threatened by being asked to screen for a physical illness such as diabetes. However, in their review Gough & Peveler (2004, this supplement) give pragmatic solutions for intervention in patients with schizophrenia. Overall, we have tried in this supplement to give suggestions, rather than be too prescriptive about the services individual psychiatrists might provide and the roles they might choose to adopt. There may be merit in reconvening the group in the months and years ahead as more data emerge.
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REFERENCES |
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Bushe, C. & Holt, R. (2004) Prevalence of
diabetes and impaired glucose tolerance in patients with schizophrenia.
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Bushe, C. & Leonard, B. (2004) Association
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Cavazzoni, P., Mukhopadhyay, N., Carlson, C., et al
(2004) Retrospective analysis of risk factors in patients
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Dinan, T. (2004) Stress and the genesis of
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Dixon, L., Weiden, P., Delananty, J., et al (2000) Prevalence and correlates of diabetes in national schizophrenia samples. Schizophrenia Bulletin, 26, 903 -912.[Medline]
Gough, S. & Peveler, R. (2004) Diabetes and
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Haddad, P. M. (2004) Antipsychotics and
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Harris, E. & Barraclough, B. (1998) Excess mortality of mental disorder. British Journal of Psychiatry, 173, 11 -53.[Abstract]
Holt, R. I. G. (2004) Diagnosis, epidemiology
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Knowler, W. C., Barrett Connor, E., Fowler, S. E., et
al (2002) Reduction in the incidence of type 2 diabetes
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Kohen, D. (2004) Diabetes mellitus and schizophrenia: historical perspective. British Journal of Psychiatry, 184 (suppl. 47), s65 -s66.
Mohan, D., Gordon, H., Hindley, N., et al (1999) Schizophrenia and diabetes mellitus. British Journal of Psychiatry, 174, 180 -181.
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Ryan, M. C. M. & Thakore, J. H. (2002) Physical consequences of schizophrenia and its treatment: the metabolic syndrome. Life Sciences, 71, 239 -257.[CrossRef][Medline]
Thakore, J. H. (2004) Metabolic disturbance in
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