May 3, 2010
Men and women who have a great sense of purpose in their lives appear to be less likely to develop Alzheimer's in old age. A goal-driven life also appears to protect against mild cognitive impairment, a serious form of memory loss that sometimes precedes Alzheimer's. The findings, published in the Archives of General Psychiatry, provide new evidence that certain character traits that may help provide protection for the aging brain.
"Alzheimer's disease is one of the most dreaded consequences of aging, and the identification of modifiable factors associated with the risk of Alzheimer's disease is a top public health priority for the 21st century, particularly given the large and rapidly increasing aging population," wrote the researchers, from Rush University Medical Center in Chicago. Encouraging a sense of purpose an older person's life may have long-term benefits for both mental and physical health.
A purposeful life is one guided by the tendency to derive meaning from life experiences and to have a sense of intention and goals that guide your behavior. For example, someone who agrees with the statements "I feel good when I think of what I have done in the past and what I hope to do in the future" and "I have a sense of direction and purpose in life" would be rated as having a high sense of purpose.
Purposefulness has long been thought to help protect against illnesses like heart disease. As this study showed, it may also protect against Alzheimer's. For the study, the researchers assessed 951 seniors living in Chicago for purposefulness. All were mentally intact and free of dementia at the start of the study, part of the ongoing Rush Memory and Aging Project.
After a study period of four to seven years, 155 of the participants had developed Alzheimer's disease. Those men and women who were rated as having the most purpose in their lives were, overall, least likely to develop Alzheimer's, mild cognitive impairment or other memory problems. Those in the top 10 percent of purposefulness were 2.4 times more likely to remain mentally sharp than those in the bottom 10 percent.
Scientists aren't sure why a sense of purpose may help to protect the brain. But having goals and purpose in life is thought to improve immune function and blood vessel health. However, there is a possibility that some of the seniors in this study who lacked purpose in their lives might already be undergoing the very earliest stages of mental decline, so it is difficult to know whether personality traits were affecting the risk of dementia or whether it was the other way around for some participants.
"Purpose in life is a potentially modifiable factor that may be increased via specific behavioral strategies that help older persons identify personally meaningful activities and engage in goal-directed behaviors," the authors wrote. "Even small behavioral modifications ultimately may translate into an increased sense of intentionality, usefulness and relevance" and improve health and psychological well-being in older adults. And nurturing a sense of purpose in life may also ward off Alzheimer's as well.
The study adds to a growing body of evidence linking lifestyle and personality traits to a reduced risk for Alzheimer's. Doctors in Sweden have found that older men and women who were easygoing and led active social lives, for example, are less likely to develop Alzheimer's disease than those who were shy and anxious. Protection against Alzheimer's was particularly strong among those who were socially outgoing and able to handle stress well, possibly because stress hormones can damage the brain.
Extraversion, or openness to interacting and talking with others, has likewise been linked to brain health. Extroverts who were calm and self-satisfied tended to have an optimistic outlook on life had a 50 percent lower risk of developing Alzheimer's than people who were nervous and prone to worry.
Conscientiousness, or a person's tendency to control impulses and be self-disciplined, is another character trait linked to a lower risk for Alzheimer's. Conscientious people also tend to be goal oriented and pursue a purpose, so those findings are consistent with the current ones.
Patricia A. Boyle; Aron S. Buchman; Lisa L. Barnes; David A. Bennett: "Effect of a Purpose in Life on Risk of Incident Alzheimer Disease and Mild Cognitive Impairment in Community-Dwelling Older Persons." Archives of General Psychiatry, Vol. 67(3), March 2010, pages 304-310.