If You Take Multiple Medications, Your Dementia Risk Soars, New Study Says

Research is looking into the link between polypharmacy and cognitive impairment.

Taking prescription medication is very much the norm in this country. Roughly half of us have been prescribed at least one medication in the last 30 days, according to the Centers for Disease Control and Prevention (CDC). The issue, some researchers suggest, is not that people are medicated, however, but about how much medication they're taking. Among those who take prescription drugs, the average number is four, per SingleCare. But the simultaneous use of multiple medicines, which is called polypharmacy, is a point of contention in the medical field. Polypharmacy has been linked to numerous health concerns, and now new research is shining more of a light on its association with dementia. Read on to find out how taking multiple medications could increase your risk of cognitive impairment.

READ THIS NEXT: 4 Common Medications That Spike Your Dementia Risk, According to a Pharmacist.

Polypharmacy has previously been linked to various health risks.

Several prescription medication bottles sit on a table. Light pours in through the windows in the background bathing the room with a soft glow. The image is photographed with a very shallow depth of field.

Polypharmacy refers to the regular use of multiple medications—typically five or more—concurrently. This has become a growing health concern, especially for older adults who are more likely to be prescribed different drugs for multiple chronic conditions, according to the National Institute on Aging (NIA). For context, roughly one-third of U.S. adults in their 60s and 70s are reportedly taking five or more prescription medications, per the CDC.

In a 2021 research report, the NIA warned that the use of excessive medications has been linked to several health concerns. That includes an increased risk of adverse drug effects, harmful drug interactions, and drug-disease interactions.

"Polypharmacy has many negative consequences," Manouchehr Saljoughian, PhD, a pharmacist at the Alta Bates Summit Medical Center in Berkeley, California, warned in an article for the U.S. Pharmacist journal in 2019.

Now, new research is looking at the connection between taking multiple medications and dementia.

A new study worked to determine a link between polypharmacy and dementia.

older man with dementiia looking out window

One of the potential adverse drug effects of excessive medication use is cognitive impairment, according to the NIA. Recently, an Oct. 11 study published in the Aging and Disease journal sought to further investigate the link between polypharmacy and dementia. Researchers from the University of Plymouth in the U.K. analyzed the medical records of more than 33,000 dementia patients in Wales from 1990 to 2015 to do this.

The new research found that 82 percent of patients were found to be taking three or more medications within the five years leading up to their diagnosis of dementia. In comparison, just 5.5 percent were using this many drugs 16 to 20 years before dementia diagnosis, according to the study.

These results highlight that taking many medications "can affect cognitive function and increase the risk of developing dementia," Naheed Ali, PhD, a doctor of internal medicine and physician writer at Medical Copywriting Services, who was not involved in the study, told Best Life.

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Previous research has also confirmed the association.


This isn't the first investigation into the link between polypharmacy and dementia. A 2019 systematic review and meta-analysis published in the Aging & Mental Health journal summarized prior research into this connection, because "the association between polypharmacy and dementia is controversial" in the health world. The researchers conducted a systematic literature review to gather six studies from 2008 to 2017.

According to the meta-analysis, these prior studies indicate that the concurrent use of five or more medications raises the risk of dementia by 30 percent. That increases even more with excessive polypharmacy: When the researchers pushed the threshold to 10 or more medications, they found that dementia risk was 52 percent higher.

"Polypharmacy, the concurrent use of multiple medications by an individual, has been found to be associated with several negative health outcomes. In this analysis, dementia was another negative health status that was associated with polypharmacy," the researchers concluded. "Additionally, excessive polypharmacy which is the concurrent use of 10 or more medications by a patient, was also associated with dementia."

Certain drug interactions can amplify cognitive impairment side effects.

A senior woman sits at a table in front of a coffee while holding her head with a distressed look on her face

There are many different types of dementia, the most common being Alzheimer's disease. But although millions of older adults in the U.S. have been afflicted, dementia isn't a normal part of aging, according to the CDC. The agency says there are many factors that increase the risk of developing dementia, including "age, family history, race, ethnicity, poor heart health, and traumatic brain injury."

But how exactly does taking multiple medications act as a risk factor for dementia?

Nancy Mitchell, a registered nurse with over 37 years of experience treating patients with dementia, says it comes down to the fact that when certain drugs interact, side effects are amplified.

"Some medications on their own may cause symptoms of cognitive decline like memory loss and brain fog, but combined with other drugs, these could place added stress on the brain and nervous system in general," Mitchell explains. "Ultimately, it increases the risk of these chronic stressors leading to long-term damage to brain cells and cognitive health at large."

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.

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