Previous studies have proposed that certain psychological factors, as well as social isolation, may contribute to the development of Alzheimer's disease. Patricia A. Boyle, from Rush University Medical Center (Illinois, USA), and colleagues explored whether purpose, defined as a "psychological tendency to derive meaning from life's experiences and to possess a sense of intentionality and goal directedness that guides behavior," can beneficially protect against Alzheimer’s Disease.  The team followed 900 community-dwelling older men and women, without dementia, enrolled in the Rush Memory and Aging Project, evaluating purpose in life and cognitive function, both at the study’s start and seven years later.  The team found that those men and women who maintained a greater sense of purpose in life as they aged, had more than a 50% reduced risk of developing Alzheimer’s Disease.  Specifically, they found that study subjects who scored highest on the purpose in life measurement scale were 2.4-times more likely to remain free of Alzheimer’s Disease (compared to those who scored lowest).  Additionally, the team found that those who developed mild cognitive impairment (MCI) reported lower purpose in life scores and had a higher number of depressive symptoms.  Writing that: “This association did not vary along demographic lines” and persisted after adjusting for confounding variables, the researchers conclude that: “Greater purpose in life is associated with a reduced risk of [Alzheimer’s Disease] and [mild cognitive impairment] in community-dwelling older persons.”