A new study has shown that individuals who have greater purpose in their lives are less likely to develop Alzheimer's disease or its precursor, mild cognitive impairment.
"Purpose in life, the psychological tendency to derive meaning from life's experiences and to possess a sense of intentionality and goal directedness that guides behaviour, has long been hypothesized to protect against adverse health outcomes," said Patricia A. Boyle, and colleagues at Rush University Medical Center, Chicago.
The researchers assessed this quality in more than 900 community-dwelling older adults without dementia who were participating in the Rush Memory and Aging Project.
Participants' purpose in life was measured by their level of agreement with statements such as, "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."
After an average of four years and a maximum of seven years of annual follow-up clinical evaluations, 155 of 951 participants (16.3 percent) developed Alzheimer's disease.
After controlling for other related variables, the researchers found that greater purpose in life was associated with a substantially reduced risk of developing Alzheimer's disease, as well as a reduced risk of mild cognitive impairment and a slower rate of cognitive decline.
The authors suggested that the biological basis of the association is unknown, but may result from the positive effects purpose of life is reported to have on immune function and blood vessel health.
The study has been published in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals.