MONDAY, Feb. 11, 2002 (HealthDayNews) -- Even a mild case of the blues can suppress your immune system and make you more likely to get sick, and it gets worse if you're older and have been depressed for a long time.
New research from Ohio State University, published in the current issue of the Journal of Abnormal Psychology, found older adults who had symptoms of depression also had decreased immune system function.
"Even a mild level of depressive symptoms can have important implications for older adults and their health outcomes," says lead researcher Lynanne McGuire, who is now a post-doctoral fellow in the Behavioral Medicine Clinic at Johns Hopkins School of Medicine in Baltimore.
About 2 million Americans over the age of 65 are believed to have diagnosable depression, according to the National Institute of Mental Health. However, the new study says another 12 percent to 20 percent in this age group could have milder cases of depression.
McGuire and her Ohio State colleagues examined 78 adults whose average age was 72.5 years. Just over half of them were caring for spouses with dementia. The group completed psychological evaluations, and had blood tests at the start of the study and again 18 months later.
From the psychological evaluations, the researchers found 22 people had symptoms of depression -- 15 from the caregiving group and seven from the non-caregiver group.
Then, they tested the blood to look at one part of immune function -- T-cell production. T-cells are "killer" cells in the immune system that attack foreign cells, such as those found in viruses and some types of cancer.
"On average, people with depressive symptoms showed poorer T-cell responses," McGuire says, which means depressed patients would be more susceptible to infectious diseases and probably some cancers.
For instance, the researchers found that at the 18-month blood test, those in the depressed group had T-cell counts that were 15 percent lower than the non-depressed group. In addition, among the depressed adults, those older than 72 had T-cell readings that were 23 percent lower than the others.
The researchers also found the severity of the depression didn't matter. What mattered more was the length of the disease.
McGuire says the study suggests there is a biological process that accompanies depression. However, she adds, researchers can't yet explain why such changes take place.
"This study establishes a relationship," says Dr. Carl Eisdorfer, director of the Center on Adult Development and Aging at the University of Miami School of Medicine. "Now, we need to figure out what's causing these changes, so that we might find ways to intervene."
Intervention, even for mild depression, may be even more important for the elderly, adds Dr. Melinda Lantz, a geriatric psychiatrist from Jewish Home and Hospital in New York.
"This study shows that even being mildly depressed can impair your immunity," Lantz says, and "immunosuppression is always more burdensome in older adults." She explains that when older people get sick, it's harder for them to function and it takes them longer to recover.
What To Do
If you have symptoms of depression, the best thing to do is talk to your doctor about it. Medications can help.
Lantz notes the elderly often don't like to complain about feeling blue, and don't tell their physicians how they're feeling. Therefore, it's important for older adults to remain active and social. If you're feeling down, join the senior center in your area or take a class -- anything to get out of the house and around other people.
For more information on depression in older people, read this from National Alliance for the Mentally Ill, or this from the U.S. Administration on Aging.
