Prevalence of mental disorders in a Canadian household population with dementia

Medical and mental health comorbidity in Alzheimer's disease and other dementias presents difficult challenges for health service delivery. However, existing studies have been conducted in clinical samples and may not be informative for planning community services. The Canadian Community Health Survey (CCHS) provides an opportunity to characterize associations between dementias and mental and physical comorbidity in a household population aged 55 and over.

Data were obtained from the 2005 CCHS-cycle 3.1. Weighted estimates for mood and anxiety disorders and other characteristics in Canadian population with dementia were calculated and were compared to those in people without the condition.

According to the CCHS, the prevalence of Alzheimer' s disease and other dementia increases with age, more or less doubling every decade. The increase among women is monotonic, whereas among men in the household population the rate of dementia peaks at age 85-89 and falls thereafter. Mood and anxiety disorders were found to be substantially more frequent among people with Alzheimer's disease and other forms of dementia compared to those without the disease (mood disorders: 19.5% vs. 5.3% and anxiety disorders: 16.3% vs. 4.0%). Heart disease, stroke and obesity were associated with dementia as was a lower level of education. Furthermore, people with dementia were more likely than those without the disease to report activity restrictions.

The high prevalence of mood and anxiety disorders in household population with Alzheimer's disease and other dementia demonstrates the burden of disease that is likely to worsen quality of life over time.