Insomnia, Anxiety Drugs May Raise Dementia Risk

By Brenda Goodman, MA
WebMD Health News

Reviewed by Louise Chang, MD

Sept. 27, 2012 -- Seniors who take certain kinds of drugs to treat anxiety or insomnia may be more likely to develop dementia than those who do not, a new study shows.

Seniors are often prescribed benzodiazepines or similar drugs to help with sleeping problems or anxiety. And even though most of these drugs are only meant to be used for a few weeks or months at a time, the drugs can be habit forming. Studies have found that many older adults stay on them longer, sometimes for years.

The new study, which is published in the BMJ, compared the risk of dementia in two groups of French seniors -- 95 who were recent users of any of 23 benzodiazepines or similar drugs at the start of the study and 968 who were not.

During the next 15 years, doctors diagnosed 253 cases of dementia. Thirty people (32%) who had taken benzodiazepines or similar drugs developed memory loss and difficulty thinking, compared to 223 people (23%) who had not taken them. Drugs used by people in this study included Ambien, Halcion, Klonopin, Restoril, Valium, and Xanax.

Even after accounting for other things that are known to affect brain function, like age, living alone, depression, high blood pressure, and diabetes, researchers found that seniors who took benzodiazepines were about 60% more likely than those who didn't to develop dementia.

Association, Not Cause

The study doesn't prove that benzodiazepines cause declines in memory and brain function. And researchers say very short-term use of the drugs is probably safe.

But other experts say seniors may want to avoid the drugs altogether.

"There is a growing body of evidence that the use of benzodiazepines is a risk factor for poor [brain function] in older adults," says Cara Tannenbaum, MD, of the University of Montreal in Canada.

Tannenbaum has recently reviewed evidence that supports a link between benzodiazepines and dementia, but she was not involved in the current research.

"In my opinion there is a very definite cause for concern, not only because of obvious memory impairment but because of the well-documented risk of falls and car accidents," she says.

A Mixed Bag

Two previous studies found that benzodiazepine users had no increased risk, or perhaps even a decreased risk of dementia, compared to seniors who didn't take the drugs.

Three other studies, on the other hand, have noted increased risks for memory trouble in benzodiazepine users.

Those studies followed people for shorter periods of time, so they couldn't rule out the possibility that people had started taking the drugs to relieve the first symptoms of dementia, which often include increased anxiety, agitation, and trouble sleeping.

The new study got around that problem by following study participants for five years before they were even considered for the analysis. This allowed researchers to exclude people who were showing signs of memory problems before they started the drugs.

Researchers say the study leaves many questions unanswered. For example, they don't know how benzodiazepines may lead to dementia. And they don't know whether their results might apply to younger people.

"We don't have a single study on this topic conducted in younger patients. We don't know if the risk of dementia is increased in people who use the drugs when they are younger -- at age 40 or 45," says researcher Bernard Begaud, MD, PhD, a professor of pharmacology at the University of Bordeaux in France.

But based on all the available evidence, Begaud says seniors may want to seek out alternatives to benzodiazepines, especially if they've been on the drugs for a long time.

"Many elderly patients take them for sleep disorders, but they might have trouble sleeping because they are depressed and they need treatment for depression, or they are drinking coffee too late in the day or they aren't exercising," he says.

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SOURCES: Billioti de Gage, S. BMJ, Sept. 27, 2012. News release, BMJ. Bernard Begaud, MD, PhD, professor of pharmacology, University of Bordeaux, Bordeaux, France. Cara Tannenbaum, MD, Michel Saucier Endowed Chair in Geriatric Pharmacology, Health and Aging, University of Montreal, Montreal, Canada.

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