Individuals who are more conscientious - in other words, those with a tendency to be self-disciplined, scrupulous and purposeful - appear less likely to develop Alzheimer's disease, according to a report in the October issue of Archives of General Psychiatry.
Conscientiousness refers to a person's tendency to control impulses and be goal-directed, and is also known as will, work and dependability, according to background information in the article. It has been associated with a wide range of mental and physical disorders, disability and death, suggesting it may be important for maintaining overall health.
Robert S. Wilson, Ph.D., of Rush University Medical Center, Chicago, and colleagues studied 997 older Catholic nuns, priests and brothers who did not have dementia when the study began in 1994. Participants underwent evaluations that included medical history, neurologic examinations and cognitive testing. Conscientiousness was measured with a 12-item inventory, where participants rated agreement with each item (for example, “I am a productive person who always gets the job done”) on a scale of one to five. Scores ranged from zero to 48, with higher scores indicating more conscientiousness. The researchers conducted follow-up examinations annually through 2006, with an average of 7.9 evaluations per person.
The participants had an average conscientiousness score of 34 out of 48. Through a maximum of 12 years of follow-up, 176 individuals developed Alzheimer's disease. Those who had conscientiousness scores in the 90th percentile (40 points) or higher had an 89 percent lower risk of developing Alzheimer's disease than those whose scores ranked in the 10th percentile (28 points) or lower. Controlling for known Alzheimer's disease risk factors did not substantially change these results. Conscientiousness also was associated with a slower rate of cognitive decline and a lower risk of mild cognitive impairment, a condition that may precede Alzheimer's disease.