(HealthDay News) -- A new study adds to growing evidence that antipsychotic drugs can raise death rates among elderly dementia patients, who are sometimes given them when their behavioral problems become too much for doctors or families to handle.

"For individual patients, the risk is small," said study author Dr. Sudeep Gill, an assistant professor at Queen's University in Kingston, Ontario, Canada. Still, "patients and their families need to talk to their doctors about the potential risks and benefits, and this study would suggest only using these drugs when other less risky approaches have been exhausted."

Antipsychotic drugs have been around since the 1950s and are typically used to treat people with mental illness, such as schizophrenia. Over time, Gill said, doctors began using them to treat behavioral problems associated with senility, also known as dementia.

The drugs had some side effects -- including Parkinson's disease-like symptoms -- but then a new generation of the medications known as atypical antipsychotics appeared. In the 1990s, they were thought to be better for elderly people and their use increased, according to Gill.

In fact, a Canadian study found that the percentage of elderly adults using antipsychotics grew from 2.2 percent in 1993 to 3 percent in 2002.

But then reports appeared suggesting the drugs were dangerous. In 2005, the U.S. Food and Drug Administration warned doctors about atypical antipsychotics, specifically olanzapine (Zyprexa), aripiprazole (Abilify), risperidone (Risperdal), and quetiapine (Seroquel).

Fifteen of 17 studies of elderly patients with dementia -- which included more than 5,100 patients -- found a 1.6- to 1.7-fold increase in death rates in those who took the drugs. Heart problems and infections like pneumonia were the most common causes of death.

For the new study, researchers looked at the risks of both the newer atypical antipsychotics and the older "conventional" drugs -- haloperidol (Haldol), loxapine (Loxitane), thioridazine (Mellaril), chlorpromazine (Thorazine) and perphenazine (Trilafon). The study authors followed 27,259 pairs of older adults in the province of Ontario who were treated for dementia between 1997 and 2003.

The patients were "paired" so the researchers could compare the death rates of patients who took atypical antipsychotics to those who didn't, and those who took conventional antipsychotics to those who took atypical antipsychotics. The researchers looked at the risk of death 30, 60, 120 and 180 days after the drugs were first given to the patients.

The researchers found that both types of antipsychotics appeared to boost death rates by 1.31 to 1.55 times. Conventional antipsychotics seemed to be the more dangerous of the two types of drugs, the researchers said.

However, the researchers said the study had limitations because it didn't look at the causes of death, and many patients didn't keep using the drugs after 30 days.

The study findings were published June 4 in the Annals of Internal Medicine.

Why does the increased risk appear to exist?

"I suspect this is because older patients are more vulnerable to adverse effects, since they much more often have underlying heart disease and problems swallowing, and the antipsychotic drug effects are the 'last straw' that precipitates a lethal event," Gill said.

Dr. James S. Goodwin, director of the Sealy Center on Aging at the University of Texas Medical Branch in Galveston, agreed with the researchers about the study's drawbacks.

An "observational" study like this one, in which researchers do not control which people take a drug, raises the prospect that the results may be caused by something other than a drug, he said.

"So the same underlying reasons that led physicians to put a patient on a treatment might be the reason for the poor or good outcome," he said. "In this case, to give just one example, patients with delirium are much more likely to be given antipsychotics, and patients with delirium are at higher risk of death."

Goodwin added that many doctors think antipsychotics are overused in older patients. However, he said, "there is a class of demented patients with real bad behavioral problems, like striking other residents in a nursing home, where antipsychotics might be the least bad solution."

SOURCES:

Sudeep Gill, M.D., assistant professor, Queen's University, Kingston, Ontario, Canada; James S. Goodwin, M.D., professor, geriatrics, and director, Sealy Center on Aging, University of Texas Medical Branch, Galveston; June 2007, Annals of Internal Medicine

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