Depression in Dutch homes for the elderly: under-diagnosis in demented residents?

Objective: Although community-based studies reported an increased incidence of depression among demented persons compared with non-demented persons, it is not clear whether this relationship also exists among institutionalised elderly persons. The aim of this study was to compare the prevalence of diagnosed depressive disorders and mood symptoms between demented and non-demented residents living in Dutch homes for the elderly.

Methods: Cross-sectional analysis in 16 homes for the elderly of routine outcome measurements by trained nurse assistants using the Resident Assessment Instrument (RAI) between January 2007 and April 2008. Nurse assistants recorded all known medical diagnoses including dementia and depression, as well as a structured observation of the presence or absence of 11 mood symptoms over the last 3 days.

Results: 313 demented and 463 non-demented residents with complete data were included (99% of all residents, mean age 84 years). 24.6% of participants were diagnosed with a depressive disorder, with no statistically significant difference between demented and non-demented persons (p = 0.237). Mood symptoms were more prevalent in demented residents (p < 0.001, OR 2.14, 95%CI 1.56-2.93). Among residents with mood symptoms, demented residents were less likely to be diagnosed with a depressive disorder than non-demented residents (p = 0.039, OR 0.61, 95%CI 0.38-0.98).

Conclusions: The prevalence of diagnosed depressive disorders was comparable between demented and non-demented residents. However, demented residents suffered more from mood symptoms and may be at risk of under-diagnosis of depression.