Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-019Mortality and Mental DisordersMichael E. DeweyTrent Institute for Health Services Research, University Hospital, Nottingham, UKINTRODUCTIONThe topic of mortality and mental illness has a long history. Evenif we discount the pioneering nineteenth century study of Farr 1 wecan still go back as far as the study of Ødega˚ rd 2 among thecontemporary studies. Both of these were, of course, patientbasedand covered all ages.Why should anyone want to study mortality and its relationshipto psychiatric illness in later life? There are many questions wemight want to ask:. Are older people with psychiatric illnesses more likely to diethan those without?. Are older people with psychiatric illnesses more likely to diethan younger sufferers after allowing for the general rise in theforce of mortality with age?. If they are more likely to die, in either case, why is this?. Whether they are more likely to die or not, do they die fromdifferent causes?. What theoretical issues does their risk of mortality raise?. What implication for service provision does their risk ofmortality, elevated or not, have?There have been some attempts at studying these issues and asmall number of relevant reviews. In this chapter there is noattempt to provide a bibliography of all the empirical studies.Instead a number of key references are chosen to illustrate themes.DEATH CERTIFICATE STUDIES OF MORTALITYA number of studies have used death certificate data to studymortality and the dementias. The primary goal of these studieshas been to estimate prevalence without the expense of performinga community study. Only one study, that of Flaten 3 in Norway,gave estimates of prevalence close to those from communitystudies, and it has been generally accepted that such studies tell usabout the death certification habits of doctors but rather littleabout the prevalence of dementias or the relationship between thedementias and mortality. There have been no such studies forillnesses other than the dementias.PATIENT-BASED STUDIESA full review of these was undertaken by van Dijk and colleagues 4which should be referred to for details of this work. For reasonsoutlined in the next section, these studies will not be furtherdiscussed here.COMMUNITY-BASED STUDIESThe primary source of information about the link betweenmortality and mental illness in this age group is the increasingnumber of community studies. Careful follow-up of well-definedseries of carefully diagnosed cases has its place, but the selectionthat goes on between primary and secondary care gives rise to therisk that the information cannot be generalized. Since most casesof dementia and depression are managed in primary care, it isthere that we must seek information on the mortality of cases ofmental disorder. One of the most comprehensive reviews of thepast few years was that of Schro¨ ppel 5 . She concluded thatrelatively little was known for either disorder.The years since Schro¨ ppel’s review have seen an explosion instudies relevant to dementia and depression. Two recentsystematic overviews have synthesized those community mortalitystudies for dementia 6 and depression 7 . Disappointingly few of theprimary studies provide effect sizes that can be combined, butthere are enough to warrant the exercise for both disorders. Fordementia, meta-analysis of six studies gave an odds ratio formortality of 2.63 (95% confidence interval 2.17–3.21). There wasweak evidence of a higher risk for vascular compared toAlzheimer’s, for increasing risk with increasing severity of dementia,and for decreasing relative risk with age. There seemed noevidence of a sex difference. For depression, meta-analysis of 15cohorts gave an odds ratio of 1.73 (95% confidence interval 1.53–1.95). There was weak evidence that men had a higher relative riskand that studies with longer follow-up have a lower risk.There have been few studies of other diagnoses in older age, andthere has been no systematic review of them. An account is givenby Langley in her review 8 .CAUSE OF DEATHOnly one study 9 appears to have addressed the problem of thecause of death in community studies of dementia. Prior to thisthere had been a number of studies of patient cohorts. Althoughthese doubtless have value, they do not help to solve the problemof the causes of differential mortality. For that we require a directcomparison between the proportion who die of cause X in thedemented group with the proportion who die of cause X in thenon-demented group. It seems so obvious that this is needed thatit is surprising that only Jagger and her colleagues 9 have addressedthe issue. They found that, relative to the general population,Alzheimer’s disease sufferers had a lower risk due to age, for beingmanual social class, and for having a history of cancer, and aPrinciples and Practice of Geriatric Psychiatry, 2nd edn. Edited by J. R. M. Copeland, M. T. Abou-Saleh and D. G. Blazer&2002 John Wiley & Sons, Ltd