Mohammed T. Abou-Saleh

512 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYSTUDIES BASED ON PSYCHIATRIC CONTACTSFrom the 1966 official figures from England and Wales forindividuals aged over 65 years, Kay 10 calculated annualincidence rates of schizophrenia of 10–15/100 000 for malesand 20–25/100 000 for females. The annual incidence of DSM-III-R-defined schizophrenia in the over-65s on the CamberwellCase Register was estimated at 12.6 per 100 000 11 . van Os andcolleagues 12 examined the annual incidence rate of late-onset(age 59+) non-affective, non-organic psychosis in 8010 elderlyadmissions to psychiatric hospitals in The Netherlands and1777 elderly admissions in the UK. The incidence of psychosisshowed a significant increase with age in both countries, thecases rising from around 10/100 000 person-years in the agegroup 60–65 years to just over 25/100 000 person-years in the90+ age group. After adjustments for the possible confoundingeffects of time trend and gender, the linear trend in theassociation between increasing age and first admission ratescorresponded to an 11% increase in incidence with each 5 yearincrease in age.COURSE AND COGNITIVE PROGNOSISLong-term follow-up of those patients we used to call ‘‘lateparaphrenics’’, but should now describe as suffering from ‘‘verylate-onset schizophrenia-like psychosis’’ 13 , has shown that in theabsence of cognitive impairment at the outset, the mortality ratedoes not differ from expectation and the causes of death in thesepatients are similar to the general population 14 . When thosepatients with accompanying organic brain syndromes andassociated cognitive impairment are included in follow-up studies,rates of progression to dementia and mortality are, notsurprisingly, high 15 .REFERENCES1. Castle DJ. Epidemiology of late-onset schizophrenia. In Howard R,Rabins PV, Castle DJ, eds, Late-onset Schizophrenia. Petersfield:Wrightson Biomedical, 1999: 139–46.2. Christenson R, Blazer D. Epidemiology of persecutory ideation in anelderly population in the community. Am J Psychiat 1984; 141: 59–67.3. Forsell Y, Henderson AS. Epidemiology of paranoid symptoms in anelderly population. Br J Psychiat 1998; 172: 429–33.4. Henderson AS, Korten AE, Levings C et al. Psychotic symptoms inthe elderly: a prospective study in a population sample. Int J GeriatPsychiat 1998; 13: 484–92.5. Tien AY. Distribution of hallucinations in the population. SocPsychiat Psychiat Epidemiol 1991; 26: 287–92.6. Keith SJ, Regier DA, Rae DS. Schizophrenic disorders. In Robins LN,Regier DA, eds, Psychiatric Disorders in America. New York: Free Press.7. Neilsen JA, Neilsen J. Prevalence investigation of mental illness in theaged in 1961, 1972 and 1977 in a geographically delimited Danishpopulation group. Acta Psychiat Scand 1989; 79: 95–104.8. Kua EH. A community study of mental disorders in elderlySingaporean Chinese using the GMS–AGECAT package. Aust N ZJ Psychiat 1992; 26: 502–6.9. Copeland JR, Dewey ME, Scott A et al. Schizophrenia and delusionaldisorder in older age: Community prevalence, incidence, comorbidityand outcome. Schizoph Bull 1998; 24: 153–61.10. Kay DWK. Schizophrenia and schizophrenia-like states in theelderly. Br J Hosp Med 1972: 369–75.11. Castle DJ, Murray RM. The epidemiology of late-onsetschizophrenia. Schizophr Bull 1993; 19: 691–703.12. van Os J, Howard R, Takei N, Murray R. Increasing age is a riskfactor for psychosis in the elderly. Soc Psychiat Psychiat Epidemiol1995; 30: 161–4.13. Howard R, Rabins PV, Seeman MV, Jeste DV. Late-onsetschizophrenia and very late-onset schizophrenia-like psychosis. AnInternational Consensus. Am J Psychiat 1999 (in press).14. Kay DWK. Outcome and cause of death in mental disorders of oldage: a long-term follow-up of functional and organic psychoses. ActaPsychiat Scand 1962; 38: 249–76.15. Holden NL. Late paraphrenia or the paraphrenias? Br J Psychiat1987; 150: 635–9.