It is no secret that depression is a particular problem among the elderly. One out of five seniors may experience symptoms of depression. A new study suggests that depression affects elderly women more than men. Not only are older women are more likely than older men to become depressed, they are more likely to remain depressed. But because women are also less likely to die while depressed than are older men, they appear to live with depression longer than do men.

Lead author of the study Lisa C. Barry, associate research scientist at the Yale School of Public Health, and colleagues evaluated a group of 754 individuals age 70 and older from 1998 to 2005. Subjects were asked to take cognitive (mental function) tests and report any medical conditions at the start of the study and at follow-up assessments conducted every 18 months. Barry and her team looked for lack of appetite, feeling sad, sleep problems and other symptoms of depression.

Published in the February Archives of General Psychiatry, the study found that 35.7 percent of the participants were depressed at some point. Women were more likely to move from being non-depressed to depressed, and were more likely to stay depressed.

And nearly 40 percent of the depressed participants were found to remain depressed over time. "This highlights the need to initiate and potentially maintain antidepressant treatment after resolution of the initial depressive episode," said Barry.

"Our findings provide strong evidence that depression is more persistent in older women than older men," said Barry. "We were surprised by this finding because women are more likely to receive medications or other treatment for depression. Further studies are needed to determine whether women are treated less aggressively than men for late-life depression, or if women are less likely to respond to conventional treatment."