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 0-470-84641-092Schizophrenic Disorder and Mood-incongruentParanoid States: Epidemiology, Prevalence,Incidence and CourseRobert HowardInstitute of Psychiatry and Maudsley Hospital, London, UKAlthough paranoid symptoms are commonly encountered in arange of psychiatric disorders that present to old age psychiatrists,remarkably few epidemiological studies of mood-incongruentparanoid states have been reported compared with cognitive andaffective disorders 1 . Because these conditions are comparativelyrare, it is difficult to determine their prevalence and incidenceaccurately. The epidemiological information that we do have onsuch states that have their onset in later life has come from twosources: studies based upon patients in contact with psychiatricservices, and surveys of the elderly general population. Because ofthe nature of paranoid states, sufferers are unlikely to cooperatewith community surveys and are often hidden from contact withpsychiatric services. Thus, all the studies reviewed below are likelyto represent underestimates of the true prevalence and incidenceof these disorders.PARANOID IDEATION AMONGCOMMUNITY-LIVING ELDERLYIn 1173 subjects aged over 64 years in the EpidemiologicalCatchment Area survey, with a response rate of 85%, generalizedpersecutory ideation, as assessed on the paranoid scale of theMini-Mult, was present in 4% 2 . There was a significant excess ofunmarried individuals among those with persecutory ideation, butno association with gender or living alone. Other associatedfeatures were visual and hearing deficits, cognitive impairment,impaired physical health and disabilities in daily living, togetherwith reduced social and economic resources. Among a communitysample of 1420 individuals aged over 75 years, paranoid ideation(defined as recording of paranoid symptoms by both a physicianand informant’s interview) was found in 6.3% 3 . The prevalence ofparanoid ideation in people with cognitive impairment was12.1%, while it was only 2.6% in those who were cognitivelyintact. Once the effect of cognitive impairment has been controlledfor, the variables significantly associated with paranoid ideationwere being divorced, being female, having depressive symptoms,receiving psychotropic drugs, having no friends or visitors, usingcommunity care and being an immigrant. In a survey of 935interviews with individuals aged 70 or over in Canberra and aneighbouring town 4 , 65 had at least one psychotic symptom; 22reported current auditory hallucinations only, 23 delusions onlyand three hallucinations and delusions: 25 of these individuals hadcognitive impairment or dementia. The point prevalence ofpsychotic symptoms was 5.7% and the significantly associatedrisk factors, apart from cognitive impairment, were living alone,male gender, limited education, social isolation, poor health anddepressive symptoms.HALLUCINATIONS INCOMMUNITY-LIVING ELDERLYData from the Epidemiological Catchment Area study were usedto estimate the self-reported age-specific prevalence of hallucinationsin a sample of 15 258 individuals of all ages. Patients withdementia were not excluded, and although the prevalence of bothauditory and visual hallucinations was highest in young subjects,an increase in auditory and visual hallucinations was found in theelderly, with a rate of visual hallucinations of 40/1000/year inmales aged 80+ 5 .PSYCHOSIS DIAGNOSED INCOMMUNITY-LIVING ELDERLYThe prevalence of schizophrenia and delusional disorder in thoseaged 65+ in the community has varied widely from study tostudy, but on the whole low rates have been found. TheEpidemiological Catchment Area survey found a prevalence ofschizophrenia of 0.2% 6 and the 6 month prevalence rate ofschizophrenia was 0.4–0.6% in a Danish survey 7 . In a sampleof 612 elderly Chinese Singaporeans examined using GMS–AGECAT criteria, 0.5% had schizophrenia or paraphreniadiagnoses 8 . From a random sample of 5222 individuals aged65+, Copeland and colleagues 9 made estimates of the prevalenceand incidence of DSM-III-R-defined delusional disorder andschizophrenia. The sample were chosen from the lists of generalpractitioners’ patients and were interviewed by nurses trained inthe use of the GMS–AGECAT computerized diagnostic system.The prevalence of DSM-III-R schizophrenia was estimated at0.12% (95% CI, 0.04–0.25%) and delusional disorder at 0.04%(95% CI, 0.00–0.14%). The minimum incidence of schizophreniafor new cases was 3.0, for new and relapsed cases 45.0, and fordelusional disorder 15.6/100 000/year. Two of the five cases ofschizophrenia identified in the sample were found to have beenfirst diagnosed before the age of 65.Principles 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