Depression raises disability risk

Depressed middle-aged adults are at four times greater risk for being unable to perform everyday tasks than their non-depressed peers, a Northwestern University study found.

"Among pre-retirement adults, limitations in life activities are strong determinants of job loss and the ability to find employment, and jeopardize an individual’s ability to live independently," said Dorothy D. Dunlop, lead author of the study, which was published in the November issue of the American Journal of Public Health.

Dunlop is research associate professor of medicine and a researcher at the Institute for Healthcare Studies and the Multidisciplinary Clinical Research Center in Rheumatology, Northwestern University Feinberg School of Medicine.

The prospect of developing disabilities in daily activities, such as dressing, bathing, walking across a room and eating, was particularly devastating for depressed African-Americans. Almost one in five depressed African American participants in the study developed a disability within two years of enrolling in the study compared with one in 20 of their non-depressed peers, results showed.

Dunlop and co-researchers used data from nearly 7,000 participants from the Health and Retirement Study, a prospective survey of community-dwelling pre-retirement adults between the ages of 54 and 65 who were free of disability at the beginning of the study in 1996.

The investigators were particularly interested in studying these pre-retirement adults because of the deleterious consequences from depression on function and health in a group at peak earnings potential whose medical costs will be imminently covered by Medicare, Dunlop noted.

As expected, persons with depression were more likely to live alone, report chronic conditions (particularly cancer and lung disease), disabilities or functional limitations, and have fewer economic resources in terms of income, wealth or greater reliance on government health insurance such as Medicaid, compared with those who were not depressed.

Together, chronic conditions and higher-level functional limitations explained over half the excess disability incidence related to depression.

These findings show that substantial excess risk from depression is related to the greater burden of health needs experienced by depressed adults compared with their non-depressed peers, the authors said.

"Public health and/or public policy programs that promote prevention and effective treatment of depression, chronic conditions and functional impairments among adults may prevent the development of activities of daily living disability, interrupting a costly spiral of health decline," they said.

Dunlop’s co-researchers on the study were Larry M. Manheim, research professor of medicine; Jing Song; John S. Lyons, professor of psychiatry and behavioral sciences; and Rowland W. Chang, M.D., professor of medicine, preventive medicine and physical medicine and rehabilitation, Feinberg School.