The Prevalence of Mental Disorders in the Elderly in Edmonton: A Community Survey Using GMS-AGECAT

Objective: To estimate the current prevalence rate of Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy (GMS-AGECAT) disorders in the elderly population in Edmonton, Alberta. To compare the prevalence rate of GMS-AGECAT depression with the prevalence rate of Diagnostic Interview Schedule-Diagnostic and Statistical Manual of Mental Disorders (DIS-DSM-III) major depression based on an earlier survey in Edmonton. Method: A sample of 1119 community residents age 65 years and over was selected using the provincial health insurance database. Data on mental disorders were collected using the Geriatric Mental State questionnaire, and diagnoses were made with the Automated Geriatric Examination for Computer Assisted Taxonomy computer program. Prevalence rates, standard errors, and logistic regression coefficients were estimated using software designed to analyze survey data. Results: The prevalence rates of GMS-AGECAT depression and organic disorder were 11.2% and 2.9% respectively. For depression there was a statistically significant difference in the prevalence rates for males (7.3%) and females (14.1%) (P = 0.003), and for organic disorder there was a statistically significant increasing trend across age-groups for females (P < 0.0001). The prevalence rate of GMS-AGECAT depression in Edmonton is comparable to rates reported from several European studies but is much higher than the 6-month prevalence rate of DIS-DSM-III major depression of 1.2% based on an earlier Edmonton survey. Conclusions: GMS-AGECAT depression is a depressive syndrome that has a larger prevalence rate than DIS-DSM-III major depression. Community surveys that measure only the prevalence rate of DSM-III major depression may be missing clinically significant cases of geriatric depression.