Researchers from Iowa State University's gerontology program have helped identify what predicts happiness and long life in centenarians, as well as what causes depression in 80-somethings and above.
In a study of 158 Georgia centenarians, the researchers found that past satisfaction with life -- even if it's simply recalling isolated career accomplishments -- is the key to happiness in our oldest years.
"The past is the best predictor of the future, so you're not going to turn your life around at 85 or 90," said Peter Martin, director of Iowa State's gerontology program and a professor of human development and family studies (HDFS), who collaborated on both studies. "But it's also good to know that past accomplishments and the happiness that you had -- looking back at your past -- carries you through these very last years."
For the depression study, researchers added 78 octogenarians (people 80 or older) to the happiness centenarian sample. They found that diminished cognitive problem-solving ability was a significant predictor of depressive symptoms in octogenarians, while living in a nursing home and greater neurotic tendencies increased depression among centenarians.
Both studies were published online in the Jan. 26 issue of the journal Gerontology. Jennifer Margrett, an assistant professor of HDFS, was the lead author on the depression study. Alex Bishop, an assistant professor of human development and family studies at Oklahoma State University (who was a doctoral student at Iowa State), was lead author of the happiness study.
In that study, researchers analyzed the subjects' responses to a series of questions that assessed their happiness, perceived health, social provisions, economic security and life satisfaction. While there was no indication that resources affect happiness, past life satisfaction -- even individual achievements -- was found to have a direct association.
Because of their results, the researchers urge caregivers of the elderly to implement programs -- including reminiscence therapy and structured life review sessions -- to foster feelings of happiness among very old populations.
"You can be not overly satisfied with your overall current capacity and physical well-being, but you can still be a very happy person because there's a lot you can contribute just by sharing some of the things that nobody knew because it was 80 or 90 years ago," said Martin, who is also in the second year of a three-year study of Iowa centenarians.
In the second other study, researchers measured depressive symptoms, demographics and functional indicators, cognition and personality in the subjects. They then compared the ability of cognition, personality, and demographic and functional indicators in explaining depressive symptoms in the octogenarians and centenarians respectively.
They were surprised to learn that overall cognition was not a stronger predictor of depressive symptoms at either age. Rather, it was the loss of the subject's control -- problem-solving in the octogenarians, and choosing where they lived in the centenarians -- that tended to depress them.