Depressed people 75 or older are just as likely to improve after an 8-week course with an inactive, placebo drug as with an antidepressant, new research indicates.

The study shows that after a short course of the antidepressant medication citalopram (CELEXA), around one-third of elderly people with depression went into remission - the same improvement rate seen in people taking a placebo drug.

However, study author Dr. Steven P. Roose of the New York State Psychiatric Institute in New York City cautioned that these findings do not suggest that the antidepressant is no better than doing nothing at all.

All of the participants in the study were treated to some kind of “active intervention,” he said. For instance, even placebo-takers received a free medical workup, an MRI, weekly visits with health professionals, and free rides to and from their appointments, among other amenities.

Moreover, seeing a marked improvement in one-third of the people taking the drug shows that something was likely helping them, Roose noted - but whether it was the drug or the supportive environment is not clear, he said.

“The response rate that you’re going to get from medicine is going to depend on the circumstances in which you give it,” Roose said in an interview. “Giving a placebo is not doing nothing.”

Roose added that Forest Laboratories, which sells CELEXA, funded the study. However, he and his colleagues designed the research, and gathered and analyzed the results, he noted.

CELEXA is a member of a family of antidepressants known as selective serotonin reuptake inhibitors (SSRIs). Although SSRIs appear to help many people, they do not seem to have the same “robust effectiveness” in older adults, Roose explained.

In contrast, another type of antidepressants known as tricyclics appear to help the elderly with depression, but carry a significant risk of side effects such as cardiovascular problems, the New York researcher said.

To investigate how CELEXA measures up to a placebo drug under optimal conditions, Roose and his colleagues asked 174 people at least 75 years of age with depression to take either CELEXA or a placebo for 8 weeks, and noted how they improved.

As Roose and his team report the results in the American Journal of Psychiatry. “The active intervention and drugs was no different from the active intervention plus placebo,” Roose told AMN Health.

He added that among people with severe depression, CELEXA-takers showed much bigger improvements than people on placebo. However, a close look at the data showed that the difference likely stems from the fact that people with severe depression responded less well to the placebo condition.

The difference is “not because the drug worked so much better, but because the placebo worked so much worse,” Roose noted.

Clearly, more research is needed to understand how best to treat older adults with depression, the researcher said.

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SOURCE: American Journal of Psychiatry, November 2004.