In 2019, about 3% of US adults ages 70-74 had dementia – that’s almost 10 million people. It seems like an inevitable path that will happen as we age, and all of us have probably rehearsed some version of the list of recommendations every New Year’s for our resolution to increase our chances of avoiding it (get exercise daily, eat healthier, sleep more and stay sharp). Now studies have shown that there might be a link between certain antidepressants and dementia. Due to the studies not being randomized controlled clinical trials, they weren’t able to make any certain claims, but the evidence does point to these drugs causing dementia.

Studies That Showed Link Between Antidepressants and Dementia

The anticholinergic study. Researchers tracked nearly 3,500 men and women ages 65 or older who took part in Adult Changes in Thought (ACT), a long-term study conducted by the University of Washington and Group Health, a Seattle health care system. They used Group Health’s pharmacy records to determine all the drugs, both prescription and over-the-counter, that each participant took in the 10 years before starting the study. Participants’ health was tracked for an average of seven years. During that time, 800 of them developed dementia. When the researchers examined medication use, they found that people who used anticholinergic drugs were more likely to have developed dementia than those who didn’t use them. Moreover, dementia risk increased along with the cumulative dose. Taking an anticholinergic for the equivalent of three years or more was associated with a 54% higher dementia risk than taking the same dose for three months or less.


The benzodiazepine study. A team of researchers from France and Canada linked benzodiazepine use to an increased risk of being diagnosed with Alzheimer’s disease. In the study, the greater people’s cumulative dose of benzodiazepines, the higher their risk.

The researchers relied on a database maintained by the Quebec health insurance program. From it, they identified nearly 2,000 men and women over age 66 who had been diagnosed with Alzheimer’s disease. They randomly selected more than 7,000 others without Alzheimer’s who were matched for age and sex to those with the disease. Once the groups were set, the researchers looked at the drug prescriptions during the five to six years preceding the Alzheimer’s diagnosis.

People who had taken a benzodiazepine for three consecutive months or less had about the same dementia risk as those who had never taken one. But those who had taken a benzodiazepine for three to six months had a 32% greater risk of developing Alzheimer’s, and those taking one for more than six months had an 84% greater chance than those who hadn’t.

The type of drug taken also mattered. People who were on a long-acting benzodiazepine like diazepam (Valium) or flurazepam (Dalmane) were at greater risk than those on a short-acting one like triazolam (Halcion), lorazepam (Ativan), alprazolam (Xanax), or temazepam (Restoril).


If You’ve Taken or Take these Drugs

It’s always good to review these medications’ potential benefits and harms with your doctor. If a drug appears problematic, the two of you can explore alternatives by considering the reason it was prescribed and seeing if there is a different type of drug that can be used as a replacement.

Don’t stop taking antidepressants on your own. It isn’t safe to quit most benzodiazepines and anticholinergic drugs “cold turkey.” Work with your clinician to develop a plan for tapering off them.


Find out more about risk factors with our dementia risk tool.



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