Dementia: Some Antidepressants May Speed Up Decline, Neuroscientists Warn

Certain types of antidepressants may accelerate the rate of cognitive decline seen in people with dementia. This is the warning of a team of researchers from Sweden, whose study of 18,740 patients found an association between the use of selective serotonin reuptake inhibitors (SSRIs) and increased cognitive impairment. SSRIs are a class of antidepressants that work by increasing the levels of the "happy hormone" serotonin in the brain. Antidepressants are commonly used to help relieve such symptoms as aggressiveness, anxiety, depression and disrupted sleep in patients with dementia. "Depressive symptoms can both worsen cognitive decline and impair quality of life, so it is important to treat them," paper author and neurologist professor Sara Garcia Ptacek of the Karolinska Institute in Solna, Sweden, said in a statement. "Our results can help doctors and other healthcare professionals choose antidepressants that are better adapted for patients with dementia."

In their study, the researchers monitored cognitive changes in 18,740 patients enrolled with the Swedish Dementia Registry between 2007 and 2018. Of these, nearly 23 percent were treated with one or more antidepressants during the study period—with a total of 11,912 prescriptions issued, 65 percent of which were SSRIs. The team found that higher doses of SSRIs were associated with a higher risk of developing severe dementia—with faster rates of decline in men than in women. Further, the team found differences between different types of SSRI—with escitalopram associated with the fastest rate of cognitive decline, followed by citalopram and sertraline. However, the researchers also caution that depression and the different severities of dementia in individual patients may be a confounding factor in the rate of cognitive decline, with further studies needed to clarify the impacts of specific antidepressants.

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These concerns over the study's potential limitations appear to be shared by other experts in the field. University of Bath, England, pharmacoepidemiologist Dr. Prasad Nishtala—who was not involved in the study—called the research "well-conducted" but cautioned that it doesn't explain, on a biological level, how or why SSRIs like citalopram and sertraline might speed up cognitive decline. He added: "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. "Additionally, there may be a 'channeling bias,' meaning that certain antidepressants like citalopram and sertraline might have been more commonly prescribed to patients with severe dementia, which could also bias the results. "Because of these limitations, the study's findings should be interpreted with caution and ideally replicated using other real-world data sources," he concluded. "As the authors themselves acknowledge, there is substantial risk with this study design for confounding by indication, which could explain the results either in part or entirely," said University College London, England, epidemiologist Dr. Emma Anderson, who was also not involved in the research. "Confounding by indication is where the outcomes we observe are actually due to the underlying reason people take these medications in the first place (e.g. mental health conditions), rather than the medication itself." "More robust study designs, which overcome this very important limitation, are needed before such bold conclusions can be made. "When based on limited evidence, these claims can be very damaging for public understanding of antidepressants, which we know help millions of people around the world." With their initial study complete, the researchers are now looking to explore whether different subgroups of patients—such as those with different types of dementia—respond in different ways to different types of antidepressants. "The goal is to find these subgroups to create more individual care," Ptacek explained. Do you have a tip on a health story that Newsweek should be covering? Do you have a question about dementia? Let us know via science@newsweek.com.

Reference

Mo, M., Abzhandadze, T., Hoang, M. T., Sacuiu, S., Grau Jurado, P., Pereira, J. B., Naia, L., Kele, J., Maioli, S., Xu, H., Eriksdotter, M., & Garcia-Ptacek, S. (2025). Antidepressant use and cognitive decline in patients with dementia: a national cohort study. BMC Medicine. https://doi.org/10.1186/s12916-025-03851-3