Mohammed T. Abou-Saleh

390 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYTable 71.2Prevalence of dysthymia, minor depression and major depression in community samples of older adultsAuthor Sample (n) Screening method FindingsBlazer et al., 1987 7 Community sample in North Carolina,USA1304 Diagnostic InterviewSchedule (DIS)0.8% with major depression, 2% withdysthymia, 4% with minor depressionCopeland et al., 1987 8 Community sample in Liverpool 1070 Geriatric Mental StateSchedule2.9% with major depression, 8.3% withminor depressionBeekman et al., 1995 9 Community sample in The Netherlands 3056 CES-D/DIS 2.0% with major depression, 12.9% withminor depressionPahkala et al., 1995 10 Community sample in Finland 1086 DSM-III diagnosis 2.2% with major depression, 14.3% withminor depressionTable 71.3.Prevalence of depression in acute care medical facilitiesAuthor Sample (n) Diagnostic method FindingsKoenig et al., 1986 12 VA inpatient sample of men 70+ 171 Screening plus modified DIS 11.5% with major depression; 23% withsignificant depressive symptomsO’Riordan et al., 1989 13 Acute medical geriatric assessmentunit111 Geriatric Depression Scale andClinical Interview4.5% with major depression; 3.6% with dysthymicdisorder; 10.8% with significant depressivesymptoms (most with dementia)experience depressive symptoms and be diagnosed with majordepression or dysthymic disorder than persons living in thecommunity.Incidence studies of depression in the elderly are extremely rarein the literature. Two studies provide some estimate of incidence,however. Rorsman et al. 18 estimated incident depression from theLundby cohort in Sweden among 2612 individuals evaluated in1957 and later in 1972 (i.e. 15 year incidence) until the age of 70.The cumulative probability of suffering a first episode ofdepression was 27% for men and 45% for women, a very highincidence figure in this cohort (especially compared to lifetimeprevalence figures, reported in other studies, of less than 15%).The annual age-standardized first incidence for depression, alldegrees of impairment included, was 0.43 for men and 0.76 forwomen. Incidence appears to decrease in the studies as individualsaged, especially for men. Eaton et al. (1997) 19 estimated theincidence of major depression over 10 years for the ECA cohortfrom Baltimore. They found an overall estimated annualincidence of 3.0 per 1000 per year, with a peak while subjectswere in their 30s, a smaller peak when subjects were in their 50sand a definite lower incidence in the elderly. Prodromal symptomswere present many years before the full criteria for majordepression were met, further linking the minor and majordepression, Foster et al. (1991) 20 estimated the incidence ofdepression in long-term care facilities. In a cohort of 104 newadmissions followed for a year, they found an incidence of 14%.One-third of these new cases were diagnosed as major depression,two-thirds as minor depression.HISTORICAL TRENDS OF DEPRESSIVEDISORDERSHistorical studies in epidemiology assist investigators to establishthe frequency of disorders in populations at different points intime. To understand the prevalence of major depression in late lifecompared to earlier stages of the life cycle in modern Westernsocieties (e.g. major depression appears to be less frequent in olderadults), an historical approach is necessary. Depressive disorders,such as tuberculosis, acquired immune deficiency syndrome(AIDS) and smallpox, wax and wane in frequency through time.Unfortunately, historical studies in psychiatric epidemiology arerare. Therefore, temporal changes in mental illness are difficult todetermine.Table 71.4.Prevalence of depression in long-term care facilitiesAuthor Sample (n) Diagnostic method FindingsParmelee et al., 1989 14Nursing home and congregateapartment residence inPhiladelphiaBond et al., 1989 15 Three British NHS nursing homes 568 Critchton Royal Behavioral Scaleand the Survey PsychiatricAssessment Scale708 DSM-IIIR checklist 12.4% with major depression; 35% significantdepressive symptoms32–42% with severe affective disorder orpsychoneurosisPhillips and Henderson,1991 16 24 Australian nursing homes 323 DSM-IIIR criteria 6.1% of residents suffered from a severedepressive episode, 6.7% from a moderatedepressive episode and 6.7% from a milddepressive episodeGerety et al., 1994 17 5 Nursing homes 135 Structured Clinical Interview forDSM-III-R diagnoses26% diagnosed with a major depressive episode