A New Study Reveals a Potential Link Between Antidepressant Use and Dementia Risk in Older Adults

By Stephanie Oehler

A study published last December in the journal BMC Geriatrics has added to the growing body of evidence that antidepressant medications may cause an increased risk of dementia in older adults. 

Researchers analyzed data from the U.S. Medical Expenditure Panel Survey to assess dementia outcomes in nearly 3,000 U.S. citizens who were followed from 2010 to 2019. Analysis of this data revealed that older adults with depression receiving SSRIs/SNRIs antidepressants had a 31 percent greater risk of developing dementia compared to those receiving psychotherapy. 

The percentage of Americans diagnosed with and seeking treatment for depression significantly increased in recent years, according to a Gallup poll. Between 2015 and 2023, the rate of individuals diagnosed with depression rose by ten percentage points, while the rate of individuals receiving treatment rose by seven points. 

The prevalence of dementia is also increasing, according to data from the Alzheimer’s Association International Conference (AAIC) in 2021. This increase, along with growing rates of depression, has led researchers to explore potential connections between these two conditions. An area of particular concern is the potential link between depression therapy medications and neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. 

“Epidemiologists have found that people with depression have a higher risk of developing Alzheimer’s disease and dementia,” said study author Dr. Hui Shao, an associate professor in the Department of Family and Preventive Medicine at Emory University. 

“We sought to investigate whether the depression itself is the primary factor contributing to higher dementia risk, or if the depression therapy medications play a more significant role”, he added. 

Previous studies have found a greater dementia risk in patients taking antidepressants compared to those without depression therapy. However, these studies have not directly compared antidepressants to other common first-line depression therapies. Shao and his team addressed this gap by investigating whether the type of depression therapy impacts dementia risk.

Shao and his team controlled for confounding factors by comparing the dementia risk among older adults with depression receiving two first-line depression therapies: SSRI/SNRI antidepressants versus psychotherapy, according to the BMC Geriatrics study.

Psychotherapy, sometimes referred to as “talk therapy,” involves an individual talking with a mental health professional to relieve mental health issues. In contrast, antidepressants are a group of medications that regulate mood and behavior by targeting certain brain chemicals, referred to as neurotransmitters. 

Individuals in the BMC Geriatrics study received Selective serotonin reuptake inhibitors (SSRI) and Serotonin-norepinephrine reuptake inhibitors (SNRIs). These drugs are considered first-line therapies due to fewer side effects compared to other classes of antidepressants. 

89 percent of patients followed received SSRIs/SNRIs, while only 11 percent received psychotherapy. 16.4 percent of the patients receiving SSRIs/SNRIs developed dementia within the nine-year study period, compared to 11.8 percent of patients receiving psychotherapy. 

Should Clinicians Rethink Antidepressant Prescriptions for Older Adults? 

Given the increase in antidepressant use in the last few decades, the question of whether the benefits of these medications outweigh the potential side effects persists. 

“Probably only 25-30 percent of people that take an antidepressant will get a benefit that really matters,” said Dr. Raison, a Professor of Human Ecology and Psychiatry in the Department of Psychiatry at the University of Wisconsin–Madison. Raison was not involved in the BMC Geriatrics study.

The convenience of these medications is why they are so frequently prescribed over other first-line treatments like psychotherapy, Raison said. 

“We have a medical system that compensates for shorter patient visits”, he added. “The ability to see a patient, ask a few questions, and very quickly put them on an antidepressant is a lot easier with modern healthcare than to prescribe somebody psychotherapy.” 

It is not yet clear whether the BMC Geriatrics study is enough evidence for clinicians to stop prescribing antidepressants. 

The study did not find a significant association for individuals who were below 65 years old, male, Black, had more severe cases of depression, or had an underlying cognitive impairment. 

“The subgroups have smaller numbers of people in them, so it’s harder to show a significant effect,” said Raison. 

This paper has a number of strengths and weaknesses. The study used data from a large patient population over nine years and removed individuals with a pre-existing dementia diagnosis from the data set. However, the study relied on past medical chart data to assess depression and dementia diagnoses, said Raison. 

Relying on medical record data may overlook people with depression and incorrectly classify others as having depression when they do not actually have it. Patients may also have already begun developing dementia but not yet have a diagnosis, he added. 

Researchers involved with the study believe their findings warrant a reevaluation of whether SSRI/SNRI should be classified as first-line treatments. “Our study serves as evidence that perhaps these popular drugs are prompting people to develop dementia more rapidly,” said Shao. “Clinicians should reassess considering antidepressants as first-line treatments for patients with depression.” 

However, Raison believes more research is needed before clinicians should change their approach to treating elderly patients with depression. “This paper, by no means, proves that using an antidepressant confers a clear risk of dementia for older adults”, Raison said. 

While the study found a 31 percent greater risk of dementia in patients receiving antidepressants, Raison said that the overall dementia risk remains low for both the antidepressant and psychotherapy groups. “We’re looking at a difference of 12 percent versus 16 percent. This study alone would not stop me from prescribing an antidepressant”, he said.

“If you wanted to do this study right, you would take a large group of depressed people that are 65 years or older, randomize them, and give half antidepressants and half psychotherapy,” Raison added. “Then, you would follow them and see if there were differences in whether they developed dementia or not.”  

While further research may be needed to fully understand the long-term implications of antidepressant use in the elderly population, the study’s findings suggest that alternative treatment options like psychotherapy may be worth considering.