Depression and anxiety is prevalent among patients with dementia but the extent to which these conditions are treated with antidepressants has not previously been investigated.
Nationwide register-based data in Denmark were used to identify all patients diagnosed with dementia or osteoarthritis at hospital admission or at first outpatient contact during the period 1995-2000. Rates of subsequent purchase of antidepressants from pharmacies were then calculated. Further, the rate of antidepressant use for patients with dementia was compared with the rate in a gender-, age-, and calendar-matched sample of the general population.
In total, 24,137 patients with a main diagnosis of dementia and 100,378 patients with a main first diagnosis of osteoarthritis were incorporated in the study. A total of 43.2% of patients with dementia received antidepressants during follow-up compared to 16.0% of patients with osteoarthritis. Among patients with a diagnosis of dementia, the rate of subsequently purchasing antidepressants was 4.17 times higher (95% CI = 4.05-4.29) than that of patients with a first diagnosis of osteoarthritis, and 8.85 times higher (95% CI = 8.68-9.03) than that of a gender-, age- and calendar-matched sample of the general population. The rate was increased in all subgroups of patients regardless of gender, age, socio-economic group and time since diagnosis.
The findings challenge the widely held contention that depression and anxiety in patients with dementia is underdiagnosed and undertreated in clinical practice.