Mohammed T. Abou-Saleh

382 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYworking class Camberwell women. In older people these observationsare consistent with the observation from several studies thatmarried older men cite their wife as their main confidante,whereas women more often cite a friend outside the home 24 . Also,in Finland, a prospective study showed that for men the risk ofonset of depression over 5 years is increased for those having pooremotional relations with their wives, while for women the risk isgreatest among those not living alone at the beginning of thefollow-up period 25 . These findings led Kivels to suggest thatmarital counselling should be made available for older people.However, there may be external factors which, to the extent towhich they affect wives and husbands and single men and singlewomen differently, may have explained some of the observedgender/marital status interaction. One such factor may be thesocial integration and activity of single men and women. Nevermarriedmen reported fewer supportive friends and neighbours,less attendance at clubs or church, and more loneliness thannever-married women in Gospel Oak 26,27 . Another area worthy ofinvestigation is the relative health of male and female maritalpartners. A national US survey showed that 64% of all spousalcarers were wives, suggesting that in older age the burden of carein marriages may generally derive from the husband and devolveon the wife 28 .DISABLEMENTOf the world population, 7–10% are significantly affected bydisablement, defined as the long-term consequences of chronicdisease 29 . These estimates have varied little between world regions,and are similar for developed and developing countries 29 . There is,however, a strong positive relationship between disablement andage. The OPCS Surveys of Disability in Great Britain reported anear doubling of disability prevalence rates with each 10 yearincrease in age, from 7% for those aged 40–49, to 67% for thoseaged 80+ 30 . Among older subjects, most detectable physicalillness is chronic rather than acute 31 .Many studies have commented on the strength of the crosssectionalrelationship between physical health variables anddepression in older age. Gurland reviewed 70 years of researchendeavour in this field, carried out in primary care, hospital andcommunity settings, and concluded that there was strongaccumulated evidence of a tendency for both physical illnessand disability to co-exist with major and minor depression at afrequency greater than that expected by chance 32 .There have been suggestions from clinical populations ofspecific associations between late-life depression and diseasessuch as stroke 33 and Parkinson’s disease 34 . Results from communitysurveys are less clear. However, stroke, respiratory diseaseand arthritis were all found to be associated by most studies whichhave assessed individual diagnoses 35–40 , while hypertension anddiabetes were less salient. This pattern of association withindividual diseases would suggest that disablement, the limitinglong-term consequences of disease, may be more relevant than anyparticular pathology. Indeed, the strongest reported associationshave generally been between depression and summary measures ofdisablement. A systematic review of the literature, using MED-LINE for the period 1984–1996 and secondary references forearlier publications, revealed 10 cross-sectional studies which hadused population samples 41 . They were consistent in reportingstrong positive associations between disablement, measured invarious ways, and depression 36–38,42–46 . However, the strongassociations might not reflect a causal relationship. Bias (somaticcontamination of the measurement of depression), confoundingand, in particular, reverse causality (depression leading todisablement, rather than vice versa) were plausible alternativeexplanations. Later prospective population-based research hasclarified the association. At least five longitudinal studies havenow shown a very strong association between disablement atbaseline and the subsequent onset of depression 47–51 . In the GospelOak survey 26,27 , after adjusting for confounders, the mostrestricted quarter of the Gospel Oak population (LondonHandicap Scale) were 20 times more likely to be depressed atbaseline than the least restricted quarter. Those among them whowere not depressed at baseline were five times more likely than theleast restricted quarter to have experienced an onset of depressionat 1 year 50 . The population attributable fraction (the proportionof new cases that might notionally be prevented if the risk factorwere removed) was 0.69. Most studies agree that it is the level ofdisablement associated with a health condition, rather than thenature of the pathology, that determines the risk for depression50,52,53 . Three population-based studies have suggested aninteraction between disablement and social support, with thestrongest effect of disablement in those with the least socialsupport 1,50,51 . Beekman et al. 1 reported that the associationbetween disablement and depression was only apparent forminor rather than major depression. However, this finding wasbased upon cross-sectional research, and requires replication.Interestingly, in community studies, disablement does not seem toinfluence directly the process of recovery from late-life depression50 .Ormel et al. 54 argue in a separate publication that synchronicityof changes in depression and disability observed longitudinally ina primary care-based study support the hypothesis that there is animportant pathway leading from depression to disability. Inreality, as most authors have acknowledged, the situation may bemore complex; the causal direction may vary between individuals,and components of each direction may co-exist within the sameindividual. A case can also be made for reciprocal causation, witha physical impairment leading to handicap, provoking depressionwhich may in turn exacerbate the degree of handicap associatedwith the original impairment.LIFE EVENTSThe literature on life events in older people was recently reviewed 55 .In the main, two methods have been used. The Bedford CollegeLife Events and Difficulties Schedule (LEDS) 56 elicits events in alengthy semi-structured recorded interview. These are then ratedindependently for contextual threat by a trained panel. Studiesusing this detailed method have shown that depressed oldersubjects have experienced more recent life events than nondepressedsubjects 57 . However, older samples differ from youngerones in that chronic difficulties are more prevalent than life events,and events typically carry relatively low levels of threat 58,59 . Also,in contrast with Brown’s work on younger adults, healthdifficulties are an important source of adversity 57,58 . The secondand more common approach has been to use a pre-determinedchecklist of events. In a community survey in the USA, the onsetof illness affecting a subject or relative, the onset of moneyproblems, and becoming a victim of crime were among the mostcommon and most undesirable life events affecting subjects aged55+ 59 . Deaths of spouses, children and siblings were rated ashighly undesirable, but were individually relatively infrequent.However, 14% of females and 12% of males experienced a familybereavement of some kind over 1 year. Most checklists focus onthese event categories, with a particular bias towards bereavementand personal illness events. Evidence for a relationship betweendepression in older age and life events measured using checklists isgenerally weaker than in LEDS-based studies. Linn 64 found asmall significant difference in the mean number of eventsexperienced by depressed and non-depressed community subjects.Other studies have not replicated this finding 60–63 . In this study,