Alzheimer's disease afflicts more than 5 million Americans—and is always fatal. In some cases the mental decline is sudden; in others the time between diagnosis and death can take more than a decade. With the number of Alzheimer's and dementia patients expected to reach as many as 16 million by 2050, researchers are racing to figure out how to prevent this devastating disease. A new study, appearing this month in the Archives of General Psychiatry, suggests that being conscientious—hardworking, goal-oriented, dependable—may lower the risk of developing Alzheimer's. Researchers studied 997 older Catholic priests, nuns and monks (average age: 75) who did not have dementia when the study began in 1994. The subjects rated themselves on a "conscientiousness scale," responding to such questions as "I am a productive person who always gets the job done." Over the 12 years of the study, 176 participants developed Alzheimer's, and they tended to be individuals who were less conscientious. NEWSWEEK's Karen Springen spoke with lead author Robert Wilson, a professor of neuropsychology at Rush University Medical Center in Chicago, about the results and their implications. Excerpts:
How much did the degree of conscientiousness matter?
The more conscientious you were, the lower your risk.
What is your definition of conscientiousness?
When you think about conscientiousness, these are mostly things our parents told us to do. We measured this trait at the beginning of the study. We read people statements, and they rated their agreement. Here are some examples: "I keep my belongings clean and neat. I'm pretty good about pacing myself to get things done on time. I have a clear set of goals and work toward them in an orderly fashion." These are people who are following rules, thinking ahead, very goal- and task-oriented. They're reliable. They're on time. Most of us know these are things we're supposed to be doing, aside from our research.
And what's the relationship between conscientiousness and Alzheimer's?
In old age, conscientiousness seems to have to do a lot with the risk of dementia. It's not that it directly affects the underlying pathology. It seems to affect your ability to tolerate the pathology and maintain normal cognitive function. The average age of death in our studies is 85. Nearly all of the participants at autopsy have at least some Alzheimer's pathology in the brain. And a little more than a third have strokes, and about 10 to 15 percent have Lewy bodies, which is a characteristic of Parkinson's.
The conscientious people's symptoms weren't as bad, even if their autopsies showed changes in the brain?
Right. In a recent study we looked at people who died without any evidence of cognitive impairment in their minds. But they had Alzheimer's disease pathology, a significant amount of it. Why is it these people aren't showing memory and thinking problems? If conscientiousness is a marker for how much you've grown and your ability to have self-discipline in life, people with low levels of conscientiousness weren't able to grow to the extent people high in the trait do. Perhaps this failing renders their brain more vulnerable, so it takes less pathology for the symptoms to show up. We don't know that it's true, but we suspect that it's true.
What should nonconscientious people do?
I don't know of any research that's looked at trying to change this trait. That's really what growing up through adulthood is, building this trait up. I suspect that most people are trying to do it. It's just that some are more successful at it than others.
Many people think of very conscientious people as being type A. Is that right, and is this good news for the type A's of the world?
Personality is complex, and there's more than one dimension to it. A type A personality trait is not one that's currently in favor. A lot of the risk of heart disease looks as if it has to do with negative emotions, like anger and depression and anxiety. In fact, that trait also predicts risk of Alzheimer's disease.
So a type A is at greater, not lower, risk of Alzheimer's?
That "type A" terminology really isn't used much, or I don't use it. When people look further at what it was about type A that seems really important, it turns out it was the negative emotion part. It's not the hard-driving, achievement-oriented person. That would be a component of conscientiousness. Think of conscientiousness as self-discipline.
How exactly did you rate the subjects' conscientiousness?
They were asked, on a scale of 0 to 4, if they agreed or disagreed with a series of statements. The statements included: "I am not a very methodical person." "I try to perform all the tasks assigned to me conscientiously." "I waste a lot of time before settling down to work." "I work hard to accomplish my goals." "When I make a commitment, I can always be counted on to follow through." "Sometimes I'm not as dependable or reliable as I should be." "I am a productive person who always gets the job done." "I never seem to be able to get organized." "I strive for excellence in everything I do."
How did you score people?
You get a total score from zero to 48. Zero would be not conscientious at all. 48 would be superconscientious. We found that your risk of developing Alzheimer's disease during the study decreased by more than 5 percent for each additional point on the scale.
You studied priests and nuns. Can we extrapolate for people of all faiths and jobs?
That's always a question of any study, and particularly a study like this, which is group of people that aren't representative of the general population. It will be important to replicate these findings. The level of conscientiousness in this group is almost exactly the level in the general population. There's no reason to think it wouldn't generalize.
When you speculate about why conscientiousness seems to help prevent Alzheimer's, you say individuals with this trait may be more likely to experience educational or occupational success—both associated with a reduced risk of Alzheimer's disease. Would the benefits of being conscientious disappear if a conscientious person failed to experience educational or occupational success?
We don't know.
So maybe conscientious CEO's are less at risk than conscientious secretaries?
That's possible, and certainly we do think that occupation and education are related to risk of disease. In this cohort, of course, they all tend to have a fairly high level of education. They've completed 18 years of education.
Were the women more conscientious?
Slightly more conscientious, which is slightly true of the general population.
Conscientiousness has been linked to being resilient and to actively coping with difficulties. Is that an even bigger reason?
Conscientious people are able to handle stresses and strains more effectively.
Do you plan to follow up on this study?
What I'm most interested in doing next year is trying to understand the neurobiologic basis of this effect. Why is conscientiousness reducing the risk of Alzheimer's? We looked at autopsies. And we found that conscientiousness was not related to how much Alzheimer's disease pathology and these other common pathologies of old age was found in your brain. This has been true of most of the lifestyle factors we've looked at. That's why we think conscientiousness is working by affecting your ability to tolerate the pathology that is accumulating in your brain and maintain your cognitive abilities. It's likely that understanding how conscientiousness works would lead to new strategies for delaying symptoms. Another important part of this is that conscientiousness also affected the development of mild cognitive impairment, the precursor for Alzheimer's. Once they have the dementia, their level of conscientiousness doesn't predict how fast the disease progresses. It looks as though conscientiousness is very important for the early stages rather than how it progresses.
Is one take-home message that parents should instill conscientiousness in their kids? Do your homework promptly, make your bed?
Parents have been trying to do that for a long time. Maybe we can think of conscientiousness as the recovery from adolescence, if you will. It's just another very strong reason for trying to instill these values and traits in others.
Are you conscientious?
I am in some ways but not in others. Conscientiousness is sort of a broad personality trait. For myself, I have a strong will to achieve, but I'm not always, shall we say, punctual and neat and clean, which is another aspect of the trait.