People with dementia don’t just lose their memories — they often battle depression, too, with specialists estimating up to half of patients experience this side effect.

But experts are now raising doubts about whether treatments meant to help are doing more harm than good, as new research suggests that some commonly prescribed antidepressants might actually speed up cognitive decline.

“Depressive symptoms can both worsen cognitive decline and impair quality of life, so it is important to treat them,” said Sara Garcia Ptacek, researcher at the Karolinska Institutet and an author of the new study. “Our results can help doctors and other health care professionals choose antidepressants that are better adapted for patients with dementia.” 

The Swedish observational study followed more than 18,700 dementia patients from 2007 to 2018. Over an average follow-up of four years, about 23% were prescribed a new antidepressant.

Selective serotonin reuptake inhibitors, which increase levels of the “feel-good” chemical serotonin in the brain, made up 65% of those prescriptions.

“Higher dispensed doses of SSRIs were associated with higher risk for severe dementia, fractures and all-cause mortality,” the researchers wrote. Men on antidepressants showed faster rates of cognitive decline than women.

The study also revealed key differences among various SSRIs: escitalopram (brand name Lexapro) was tied to the fastest cognitive decline, followed by citalopram (Celexa) and sertraline (Zoloft).

Swedish researchers stressed that it’s still unclear whether the cognitive decline observed was due to the antidepressants or other factors, such as the depressive symptoms themselves.

Experts not involved in the study urged caution in interpreting the findings, warning that more research is needed to fully understand the risks and benefits of antidepressants for dementia patients.

“There are some important limitations that should be considered,” said Prasad Nishtala, a researcher at the University of Bath in the UK. “One major issue is that the severity of depression in dementia patients wasn’t fully accounted for, which has the potential to bias the results.”

Dr. Richard Isaacson, a preventive neurologist and director of research at Florida’s Institute for Neurodegenerative Diseases, told CNN that while doctors probably won’t alter their treatment plans based on this study, the public reaction could pose a problem.

“As a clinician, the worrisome thing is that a patient’s loved one will hear about this study and say, ‘Oh, if we use an antidepressant, my mom will decline faster,’” he said.

“Then what happens to the patient’s quality of life? Could they become more agitated and be a danger to be kept at home?” Isaacson asked. “Could they become more withdrawn, socially restricted and apathetic? Very probably.”

Research suggests that almost 10% of US adults 65 and older have dementia, while another 22% have mild cognitive impairment.

Along with memory loss, many people with dementia also undergo significant mood and behavioral changes.

Antidepressants are commonly prescribed to help manage these symptoms, with a 2020 study finding that of more than 737,000 people who have dementia, nearly half of them received these medications. However, experts say research on antidepressants’ therapeutic benefit for dementia patients remains limited.

A 2019 review found that antidepressants are often ineffective at treating depression in people with Alzheimer’s disease, the most prevalent form of dementia in older adults. 

These drugs are also frequently used to manage anxiety in dementia patients, though their value in this area is similarly unclear. 

In a 2025 analysis of seven trials, five of them found no improvement in anxiety after antidepressant treatment or no difference when compared to a placebo. Only two studies showed some benefit of citalopram, but further research is needed to confirm its effectiveness.

The Swedish research team said its findings could help doctors make more informed treatment decisions. They 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 individualized care,” Garcia Ptacek said.