The influence of cognitive decline on well-being in old age.

This study addressed the hypothesis that late life cognitive decline leads to loss of well-being. Participants are older persons from the Rush Memory and Aging Project. Beginning in 2001, they underwent annual clinical evaluations that included detailed cognitive performance testing and a 10-item self-report measure of purpose in life, an aspect of well-being. Initial analyses involved 1,049 individuals who were without dementia at baseline and followed a mean of 5.0 years. The intercepts and slopes of global cognition and purpose were positively correlated, and level of cognition at a given evaluation predicted level of purpose at the subsequent evaluation, consistent with the study hypothesis. Purpose also predicted subsequent cognition. These findings persisted in analyses that excluded mild cognitive impairment or controlled for time varying levels of depressive symptoms or disability. To see whether cognitive decline's correlation with purpose differed from its correlation with other aspects of well-being, we conducted additional analyses on a subgroup of 560 persons without dementia who completed a multidimensional measure of well-being once between 2008 and 2011. More rapid cognitive decline in the period preceding well-being assessment (M = 5.5 years, SD = 2.8) was associated with lower level of nearly all aspects of well-being (5 of 6 measures), but the extent of the association varied across well-being dimensions and was stronger for purpose than for self-acceptance and autonomy. The results support the hypothesis that cognitive aging leads to diminished well-being, particularly aspects such as purpose in life that involve behavioral regulation.