Moderate, regular exercise may be just as helpful in combating serious depression in older people as anti-depressant medication, says a recent report by scientists at Duke University Medical Center.
Duke researchers studied 156 middle-aged to elderly individuals over a five-year period who suffer from major depressive disorder, also known as MDD. The participants were divided into three groups: one that exercised only, one that exercised and took anti-depression medication, and one that took medication only. The exercisers were asked to walk around a track for 30 minutes three times a week and had not been exercising previous to the study.
After 16 weeks, the scientists used structured interviews with and self-evaluation by the participants to measure their symptoms according to the definition of MDD found in the psychiatric reference book Diagnostic and Statistical Manual IV as well as on the Hamilton Rating Scale for Depression.
Symptoms of MDD by the DSM-IV definition involve depressed mood or loss of interest or pleasure combined with at least four of the following: sleep disturbances, weight loss, changes in appetite, psychomotor agitation, feelings of worthlessness or excessive guilt, impaired cognition or concentration and recurrent thoughts of death. Based on this definition, 60.4 percent of the patients who only exercised were no longer depressed after 16 weeks, compared with 65.5 percent for the medication group and 68.8 percent of the combination group.
The differences in results using both forms of measurement are not statistically significant, said Duke psychologist James Blumenthal, the lead researcher on the project. He and his colleagues did note that patients who took the anti-depressants saw their symptoms relieved sooner, but by 16 weeks the group differences had disappeared.
The statistical similarity came as a surprise, said Blumenthal. One possible explanation for this could be in the structured and supportive social environment that went along with participating in exercise part of the study. To test this hypothesis, Blumenthal intends to begin a study to gauge the effect of exercising in a less supportive atmosphere, where participants perform their exercise at home or alone. He also plans to include a no-treatment control group.
"If you bring up medication, often people don't want to take it," says Dr. Joseph Gallo, assistant professor of Family Practice and Community Medicine at the University of Pennsylvania in Philadelphia. He says that elderly patients often deny depressive symptoms, and that using exercise to treat those symptoms could be effective because exercise builds on "self-efficacy and self-confidence.- But not everyone will benefit from exercise, cautions Gallo. Because depression plays a role in how people take care of themselves, he points out it's unlikely all depressed people will be motivated to start or keep exercising. Additionally, older adults may have medical complications that prohibit them from being active. The disability can contribute to their depression, he says, but also makes movement an impossible treatment for them.
Blumenthal also suggested that exercise might be beneficial because patients are actually taking an active role in trying to get better. "Simply taking a pill is very passive. Patients who exercised may have felt a greater sense of mastery over their condition and gained a greater sense of accomplishment. They felt more self-confident and had better self-esteem because they were able to do it themselves, and attributed their improvement to their ability to exercise," he said.
"While we don't know why exercise confers such a benefit, this study shows that exercise should be considered as a credible form of treatment for these patients. Almost one-third of depressed patients in general do not respond to antidepressant medications, and for others, the antidepressants can cause unwanted side effects," said Blumenthal.
The anti-depressant used in the study was sertraline, which is a member of a class of commonly used anti-depressants known as selective serotonin reuptake inhibitors. The trade name for sertraline is trade name Zoloft.
Blumenthal stressed that the study did not include patients who were acutely suicidal or suffered from what is termed psychotic depression. Furthermore, participants were recruited by advertisements and so were both interested in exercise and motivated to get better.
The results of the study were published in the Oct. 25, 1999 issue of The Archives of Internal Medicine.