Edition: U.S. / Global

VITAL SIGNS: AGING; Mild Depression and Eroding Immunity

By Eric Nagourney
Published: February 12, 2002

Scientists have long known that there is a link between serious depression and the ability to ward off diseases.

But a new study suggests that even mild depression can weaken the immune system in older people if it goes on long enough.

Writing in the current Journal of Abnormal Psychology, researchers from Ohio State University said that among people they had monitored for 18 months, those who reported symptoms of depression had measurably lower immune responses, as determined through blood samples.

The symptoms probably need to occur over a long period to affect the immune system, said the lead author, Dr. Lynanne McGuire, now of the Johns Hopkins medical school.

''It wasn't someone having a bad week or a bad day,'' Dr. McGuire said.

In this case, many of the people studied were under considerable stress, since they were the spouses of dementia patients taking part in a broader study.

In all, the researchers examined 78 adults, with an average age of about 72. Of these, 22 were judged to be mildly to moderately depressed after taking a standardized questionnaire about their emotional well-being.

The immune system generally declines as people age, leaving them more vulnerable to disease and less equipped to recover quickly. So anything that accelerates that deterioration is of concern, the researchers said.

Moreover, they found, the older the person, the worse the effect even mild depression seemed to have.

Still, the study does not mean that mildly depressed elderly people necessarily need to be taking antidepressants, Dr. McGuire said. She said they might well benefit from simple therapy, or even just someone making sure they were getting enough physical activity.

Drawing (Illustrations by Stuart Goldenberg)