Older women taking antidepressants face significantly higher risks of stroke and death when compared with their generational cohorts who don't take the drugs, a U.S. study has determined.
In what one of the researchers called the first major look at the mental health of women 50 and older, investigators found that women using antidepressants had a 32 percent higher risk of death than nonusers when all causes of mortality were examined. Their risk of suffering a stroke, fatal or nonfatal, was 45 percent higher.
However, the study found no difference in the frequency of heart attacks of any kind. And the study could not tease apart whether the cause of the higher rates of strokes and deaths among the older women taking antidepressant drugs was the treatment or the depression.
"This study may provide one more piece of information as we learn what are the advantages and disadvantages of different approaches to depression. The study wasn't able to answer some important questions, such as how much [of the outcome] is due to medication and how much to depression itself," said lead author Dr. Jordan W. Smoller, a psychopharmacologist associated with the Massachusetts General Hospital Department of Psychiatry.
The study's other author, Sylvia Wassertheil-Smoller, told The Washington Times that antidepressants could be at fault, though.
"It has been known that older types of antidepressant agents have some cardiac effects," said Ms. Wassertheil-Smoller, an epidemiologist at Albert Einstein College of Medicine in New York and Dr. Smoller's mother.
The study was published in the Dec. 14 online edition of Archives of Internal Medicine. Researchers from six other institutions contributed to the study.
The risks overall for the women, ages 50 to 79, was relatively small -- 0.43 percent for stroke annually for users versus 0.3 percent for nonusers -- but the findings were significant because of the large number of patients involved, the researchers said.
Results were based on a further examination of data from the federal Women's Health Initiative (WHI) study, a 40-center project funded by the National Institutes of Health that was begun in 1994.
The project had 136,293 participants ages 50 to 79 -- "a unique cohort of women," said Ms. Wassertheil-Smoller.
The study compared 5,496 women taking the drugs to 130,797 not taking the drugs.
Antidepressants are among the most widely prescribed drugs in the U.S., especially among postmenopausal women, she noted, perhaps because "women are more willing to confront depression than men. Interestingly, in the WHI, women 70 to 79 had lower rates of depression than women who were younger. I don't know what happens after 79. We still are assessing depression. There is a lot of genetics in that."
Other studies have shown that depression can be a risk factor for cardiovascular problems, and Ms. Wassertheil-Smoller said the benefits of antidepressant drugs may still outweigh the risks.
"We hope [women] won't stop taking antidepressants because depression itself is a risk factor, not to mention a debilitating condition," she said. "If you are considering taking a drug for a common cold, you would not want to take one with side effects, because the cold will go away anyway. If it is cancer, you will measure it differently. The risks of the antidepressants we found in absolute terms are not that high."
Ms. Wassertheil-Smoller said the most surprising finding was that selective serotonin reuptake inhibitors (SSRIs) such as Zoloft and Prozac had more side effects than had been hoped.
"It turned out that newer ones, the SSRIs, were not protective, and that was a surprise," she said.
She said she hopes that publication of the study will influence drug companies to develop better antidepressants and get women to pay more attention to their cardiovascular risk factors.
"Hypertension is a risk factor for stroke and death and it is very badly controlled in the U.S. Although it has improved somewhat in the last decade, it still is far short of what it should be and it rises with age," she said.
Another issue that might be a contributing factor to this, she said, was the fact that "an old woman may not be treated as aggressively as middle-aged men. Plus, older people tend not to adhere to medications, and then some people can't afford them."
The survey, she said, was observational and not a strictly clinical study with control groups and close monitoring.
"We don't have clinical corroboration of depression. There was no psychiatric interview to see if a woman was depressed. We did screening as epidemiologists that has a lot of false positives and negatives," she said.