The women in the depression study were also less likely to die while depressed than were older men, indicating that women live longer with depression than men. This factor, along with the higher likelihood of women becoming depressed and remaining depressed, collectively contribute to the higher burden of depression among older women,according to the researchers.
Depression is known to be more common among women than men in the later years, but the reasons for this gender imbalance have been unclear, Dr. Lisa C. Barry from the Yale School of Public Health, New Haven, Connecticut and colleagues explain. To investigate, they followed 754 men and women 70 and older for 7 years, checking on their mental health every 18 months. At each evaluation point, the researchers found, the women were more likely than the men to have transitioned from a non-depressed to a depressed state.
Overall, women were about twice as likely as men to become depressed, while they were 73 percent less likely to transition from being depressed to being non-depressed. And depressed women were 73 percent less likely to die during the study's follow-up than their male peers.
Almost 40 percent of people who were depressed during the study were depressed for at least two evaluation points in a row, underscoring the importance of treating depression and maintaining treatment if needed even after the initial episode of depression has lifted, the researchers say.
"Our findings provide strong evidence that depression is more persistent in older women than older men," Barry said in a statement. The findings are "somewhat surprising" given that women are generally more likely to receive drug or non-drug treatment for depression, she and her colleagues note.
"Whether women are treated less aggressively than men for late-life depression or are less likely to respond to conventional treatment is not known, but should be the focus of future research," the researchers concluded.