Severe Psychiatric Disorders in Mid-Life and Risk of Dementia in Late- Life (Age 65-84 Years): A Population Based Case-Control Study

Abstract

Objective: To examine the association of mid-life exposure to several psychiatric disorders with the development of late-life dementia. Methods: A matched case-control study using Western Australian state-wide hospital inpatient, outpatient mental health and emergency records linked to death records. Incident dementia cases (2000-2009) aged 65 to 84 years were sex- and age-matched to an electoral roll control. Records as far back as 1970 were used to assess exposure to medical risk factors before age 65 years. Candidate psychiatric risk factors were required to be present at least 10 years before dementia onset to ensure direction of potential causality. Odds ratios were estimated using conditional logistic regression. Results: 13, 568 dementia cases (median age 78.7 years, 43.4% male) were matched to a control. Depression, bipolar disorder, schizophrenia, anxiety disorder and alcohol dependence were found to be significant and independent risk factors for late-life dementia after adjusting for diabetes, heart disease, cerebrovascular disease and smoking risk factors. The effect of a history of depression, schizophrenia and alcohol dependency on dementia risk varied with age, being strongest for earlier onset late-life dementia and waning at older ages. Conclusion: Severe depression, anxiety disorder, bipolar disorder, schizophrenia and alcoholic dependency disorder treated by specialists in psychiatric facilities in mid-life are important risk factors for late-life dementia. These psychiatric conditions need to be considered in future studies of the risk and prevention of late-life dementia.

Dementia onset, incidence and risk in type 2 diabetes: a matched cohort study with the Fremantle Diabetes Study Phase I

“…In Australia, the sensitivity, positive predictive value and κ value for ICD-10 dementia diagnoses in hospital records were 67%, 76%, and 0.71, respectively, suggesting substantial agreement between medical charts and registry data [41]. We have previously demonstrated that the use of combined databases in WADLS substantially increases the detection of individuals with dementia [26,28]. In a Danish study, 86% of dementia and 81% of Alzheimer's disease diagnoses in hospital registers were correct, while the accuracy for vascular dementia was lower [42].…”

“…Dementia case and comorbidity ascertainment All hospital admissions, contacts with mental health services and deaths in Western Australia are recorded in the WADLS [25], and the combination of databases has been shown to improve the identification of individuals with dementia [26][27][28]. The WADLS was used to determine prevalent dementia status at study entry from ICD coding from 1982 and incident dementia to the end of June 2012.…”

“…This includes history of myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, chronic pulmonary disease, rheumatic disease, peptic ulcer disease, hemiplegia or paraplegia, renal disease, liver disease and cancer. We extracted and included a history of schizophrenia from the HMDS and MHIS databases given its associations with diabetes and dementia [28,31].…”

Long-term Risk of Dementia in Persons With Schizophrenia

“…41 These findings indicate that both neurobiological and environmental factors could contribute to the excess risk of dementia in persons with schizophrenia. Four previous longitudinal studies identified a total of 196 persons with schizophrenia who developed a clinical dementia diagnosis [15][16][17][18] ; the studies found relative risks for the development of dementia ranging from 2.4 to 16. As the median age at onset is 28 years for schizophenia 19 and 81 years for size and follow-up time to include all persons with schizophrenia and allow for a sufficient induction period between a diagnosis of schizophrenia and a diagnosis of dementia.…”

“…Four prior studies have compared the risk of dementia among persons with vs those without schizophrenia using clinical dementia diagnoses, and their findings ranged from a 2.4-fold to a 16-fold higher risk of developing dementia. [15][16][17][18] However, those studies were limited because they did not include individuals with onset of schizophrenia before the age of 30 years [16][17][18] (potentially effecting generalizability, as the majority of persons with schizophrenia are diagnosed before the age of 30 years 19 ) or had an insufficient duration of follow-up for the cohort to display a clinically significant risk of developing dementia. 15 Furthermore, a recent review of 20 longitudinal studies using cognitive screening tools or neuropsychological tests to examine the risk of cognitive decline (ie, beyond what can be attributed to the pathophysiologic factors of schizophrenia itself) in persons with schizophrenia found inconsistent results: 12 studies suggested significant cognitive decline, whereas 8 studies did not find a significant association.…”