Data from over 900 community-dwelling older adults participating in the Rush Memory and Aging Project has 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. Specifically, those scoring in the top 10% of a purpose in life measure (4.2 out of 5) were approximately 2.4 times more likely to remain free of Alzheimer's disease than individuals in the bottom 10% (score of 3.0). The association was independent of sociodemographic status, depression, neuroticism, social network size, and number of chronic health conditions.
(2010). Effect of a Purpose in Life on Risk of Incident Alzheimer Disease and Mild Cognitive Impairment in Community-Dwelling Older Persons.
Arch Gen Psychiatry. 67(3), 304 - 310.