Preventive treatments for people in the high-risk group hold promise for providing the greatest health benefit at the lowest cost, the researchers concluded.
“People with low-level depressive symptoms, who perceive that they have poor quality social support from other people, and with a past history of depression, were at particularly high risk to develop new major depression within the one-to-four year time period of the study,” Lyness said. “This is good news, as we in the field are just learning how to prevent depression in particular high-risk groups. Future work will be able to test whether any of a variety of treatments—perhaps psychotherapy, perhaps medication, perhaps other things such as exercise—will help to prevent depression in persons suffering from the risks we identified in this study.”
More than 600 people who were 65 years of age or older took part in the study. They were recruited from private practices and University-affiliated clinics in internal medicine, geriatrics and family medicine in Monroe County, N.Y. Only participants without an active diagnosis of major depression were included in the analyses.
Annual follow-up in-person interviews were conducted for up to four years. Information obtained from telephone contacts and annual medical chart reviews supplemented the interviews. Thirty-three participants, or about 5.3 percent, developed an episode of major depression during the study period.
In their analysis, the researchers concluded the “number needed to treat,” an epidemiological measure used in determining the effectiveness of a medical intervention, was five. This means the fully effective preventive treatment of five individuals presenting the indicators would prevent one new case of major depression.
In an editorial in the journal, Warren D. Taylor, M.D., associate professor of Psychiatry at Duke University Medical Center, agreed the number needed to treat was low and indicated cost effectiveness.
“Given the complications of depression in an elderly population, a preventive approach for this at-risk population may be quite important to not only prevent psychological suffering but to also avoid the deleterious effects of depression on comorbid medical illness,” Taylor wrote.
The researchers concluded “the present study may inform current clinical practice by fostering early detection and intervention critical to improving patient outcomes for depression.”
In addition to Lyness, authors of the article include: Wan Tang, Ph.D., research assistant professor of Biostatistics, Xin Tu, Ph.D., professor of Biostatistics and of Psychiatry, Yeates Conwell, M.D., professor of Psychiatry, and Qin Yu, Ph.D., research associate at the University of Pennsylvania.
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