The number of older Americans taking three or more brain-affecting medicines has more than doubled in just a decade, a new study from the University of Michigan and VA Ann Arbor Healthcare System finds.

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The sharpest rise occurred among seniors living in rural areas, where the rate of doctor visits by seniors taking combinations of such drugs — opioids, antidepressants, tranquilizers and antipsychotics — more than tripled.

This "polypharmacy" of drugs that act on the central nervous system is concerning, the researchers say, because of the special risks to older adults that come with combining such medications. Falls — and the injuries that can result — are the chief concern, along with problems with driving, memory and thinking.

Combining opioid painkillers with certain other drugs such as benzodiazepine tranquilizers, commonly used for anxiety, sleep and behavior issues, is of particular concern. Recently, the Food and Drug Administration issued the strongest possible warning against this combined use because of an increased risk of death.

Publishing in JAMA Internal Medicine, the report details findings from the team's analysis of Centers for Disease Control and Prevention data, gathered through the National Ambulatory Medical Care Survey from a representative sample of doctors' offices between 2004 and 2013.

While only 0.6 percent of doctor visits by people older than 65 involved three or more drugs affecting the central nervous system in 2004, the number had risen to 1.4 percent in 2013. Applying that percentage nationwide means 3.68 million doctor visits a year involve seniors taking three or more such drugs.

"The rise we saw in these data may reflect the increased willingness of seniors to seek help and accept medication for mental health conditions — but it's also concerning because of the risks of combining these medications," says Donovan Maust, M.D., M.S., the study's lead author and a geriatric psychiatrist at Michigan Medicine, the U-M academic medical center.

Also an issue: Nearly half of seniors taking these drug combinations did not appear to have a formal diagnosis of a mental health condition, insomnia or a pain condition — the three chief concerns they're usually prescribed for.

"We hope that the newer prescribing guidelines for older adults encourage providers and patients to reconsider the potential risks and benefits from these combinations," he says.

In 2015, the American Geriatrics Society updated its guideline for the use of prescription drugs in older people, called the 2015 Beers Criteria.

Some of the medication groups that affect the central nervous system have been on the Beers Criteria list since it was first published in 1997, but this update is the first to raise concern about the polypharmacy as potentially inappropriate.

Related work

Maust, who is an assistant professor of psychiatry at the U-M Medical School, recently published two other papers with colleagues from U-M and the Ann Arbor VA on the use of central nervous system-affecting drugs in older people.

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In the December issue of the Journal of the American Geriatrics Society, they reported that 5.6 percent of doctor visits by people 65 and older included a prescription for a benzodiazepine tranquilizer in 2010.

More than a quarter of those visits also included a prescription for an antidepressant, and 10 percent included a prescription for an opioid drug. Only 16 percent of those who were continuing to receive a benzodiazepine prescription had a diagnosis of a mental health condition. Almost no patients were referred to psychotherapy.

The data for this study also came from the CDC's National Ambulatory Medical Care Survey from 2007 to 2010.

"Prescribing of benzodiazepines to older adults continues despite decades of evidence showing safety concerns, effective alternative treatments and effective methods for tapering even chronic users," says Maust.

Meanwhile, in a paper published online in Psychiatric Services in January, the team reports that more than half of 231 older patients whose primary care doctors prescribed them an antidepressant for depression (as opposed to off-label use for sleep, for example) did not meet the criteria for a major depressive disorder.

The patients were participating in a randomized controlled trial aimed at improving depression outcomes and are not considered a representative sample of older Americans, but Maust says the team's findings could indicate an overprescribing trend.

Maust and colleague Helen Kales, M.D., also wrote an invited commentary in JAMA Internal Medicine in January about the use of drugs that affect the central nervous system to "medicate distress" in older people.

Maust and Kales are members of the U-M Institute for Healthcare Policy and Innovation and the VA Center for Clinical Management Research.