Study explores link between antidepressant use and cognitive decline in dementia patients

New research suggests that antidepressants can accelerate cognitive decline in people with dementia. At the same time, some drugs appear to be less harmful than others, which can help doctors make better treatment decisions, according to the study published in BMC Medicine.

Antidepressants are often used to relieve symptoms such as anxiety, depression, aggressiveness, and sleep disturbances in dementia sufferers.

However, a new observational study based on data from the Swedish Dementia Registry (SveDem) shows that patients with dementia who are treated with antidepressants experience an increased cognitive decline compared to patients who do not receive this medication.

The study is based on a comprehensive analysis of registry data from 18,740 patients, of whom approximately 23 percent were treated with antidepressants. During the course of the study, a total of 11,912 prescriptions of antidepressants were registered, with selective serotonin reuptake inhibitors (SSRIs) accounting for 65 percent.

"Depressive symptoms can both worsen cognitive decline and impair quality of life, so it is important to treat them. Our results can help doctors and other healthcare professionals choose antidepressants that are better adapted for patients with dementia," says Sara Garcia Ptacek, researcher at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, and the study's last author.

The researchers from Karolinska Institutet and Sahlgrenska University Hospital in Gothenburg have followed the patients' cognitive development over time and compared both medicated and non-medicated groups as well as different types of antidepressants.

Although it is not currently possible to determine whether the cognitive impairment is due to the drugs or to the depressive symptoms themselves, the researchers were able to see that antidepressants were associated with increased cognitive decline.

Differences between drugs

The study also points to differences between different drugs. The SSRI escitalopram was associated with the fastest cognitive decline, followed by the SSRIs citalopram and sertraline.

Mirtazapine, which has a different mechanism of action, had less negative cognitive impact than escitalopram.

The researchers now want to investigate whether certain patient groups, such as people with specific dementia types or biomarkers, respond better or worse to different antidepressants.

The goal is to find these subgroups to create more individualised care."

Sara Garcia Ptacek, Researcher, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet

The study has been funded by the Swedish Research Council, Region Stockholm, the Swedish Dementia Research Foundation, the Alzheimer's Foundation and New Innovative Roads Call - a private initiative from the Leif Lundblad family and others. The researchers report no conflicts of interest.