Mental illness among persons with and without dementia in continuing care: A multi-jurisdictional, repeated cross-sectional study

Background Limited epidemiologic data exists for mental illnesses among at-risk home care (HC) and residential long-term care (LTC) recipients. Objective To estimate the annual prevalence (April 1, 2012-March 31, 2023) of various mental illnesses among HC and LTC populations (versus matched comparators) with and without dementia in the Canadian provinces of Ontario, Alberta, and Manitoba. Methods Parallel repeated cross-sectional studies were conducted in each province using linked health administrative data. HC and LTC recipients aged ≥18 years were matched to comparators on demographics, dementia and comorbidity. Prevalence estimates were derived using validated case definitions for any mental illness, mood/anxiety disorders, depression and anxiety (with/without drug claims), schizophrenia, bipolar disorder and suicide attempt. Prevalence ratios (95% CIs) were estimated with modified Poisson regression models. Results Included were 682,466 HC clients and 233,499 LTC residents. Mental illnesses were common in HC and LTC settings across all three provinces. Prevalence estimates were typically higher among care recipients versus matched comparators and among persons with versus without dementia. Up to 70% of HC clients and 80% of LTC residents with dementia had any mental illness; in both settings, 40% had mood/anxiety disorders, 4% bipolar disorders, and between 2%-6% schizophrenia. Suicide attempts were rare (0.5–0.6%). Prevalence varied by province and was higher for case algorithms including drug claims. Conclusions The high prevalence of mental illness and its common co-occurrence with dementia in HC and LTC recipients illustrates the complexity and challenges of care in these populations and raises concerns about potential unmet mental health needs.