Long-term treatment with certain antidepressants may reduce dementia incidence

Long-term treatment with certain antidepressants appeared associated with reduced dementia incidence, according to results of a case-control study published in Journal of Clinical Psychiatry.

“Depression could represent one of these potentially modifiable risk factors for all-cause dementia,” Claudia Bartels, PhD, of the department of psychiatry and psychotherapy at University Medical Center Goettingen in Germany, and colleagues wrote. “Numerous studies have concordantly demonstrated a strong association between depression and an increased risk [for] subsequent dementia. Selective serotonin reuptake inhibitors (SSRIs) are commonly used to treat depressive symptoms in [Alzheimer’s disease] dementia.

“Preclinical research in recent years has suggested that SSRIs reduce amyloid plaque burden in transgenic mouse models of [Alzheimer’s disease] and in cognitively healthy humans, attenuate amyloid-[beta]_1-42–induced tau hyperphosphorylation in cell culture and improve cognition in mice.”

However, the effects of SSRIs on cognition in Alzheimer’s disease dementia were linked mostly to negative results in randomized clinical trials; research is sparse regarding which antidepressants may influence risk for developing dementia; and evidence is particularly rare for treatment duration effects on this risk. Thus, Bartels and colleagues sought to determine the effects of antidepressant drug classes and individual compounds with various treatment durations on the risk for developing dementia. The researchers analyzed data of 62,317 individuals with an incident dementia diagnosis who were included in the German Disease Analyzer database, and they compared outcomes to those of controls matched by age, sex and physician. They conducted logistic regression analyses, which were adjusted for health insurance status and comorbid diseases linked to dementia or antidepressant use, to evaluate the association between dementia incidence and treatment with four major classes of antidepressant drug, as well as 14 of the most commonly prescribed individual antidepressants.

Results showed an association between treatment for 2 years or longer with any antidepressant and a lower risk for dementia vs. short-term treatment among 17 of 18 comparison. Particularly for long-term treatment, herbal and tricyclic antidepressants were linked to a decrease in incidence of dementia. Long-term treatment with escitalopram (OR = 0.66; 95% CI, 0.5-0.89) and Hypericum perforatum (OR = 0.6; 95% CI, 0.51-0.7) were associated with the lowest risks for dementia on an individual antidepressant basis.

“Clinical trials — although well acknowledged as the gold standard procedure — have debunked numerous promising compounds and become increasingly challenging with longer treatment durations,” Bartels and colleagues wrote. “Thus, and in awareness of the controversy of this suggestion, analyzing data from registries in a naturalistic setting may be an attractive and feasible alternative. If individual datasets could be combined in a multinational effort, even more powerful analyses of merged big databases could be performed and an additive contribution with naturalistic data could be made.”