Among cognitively normal people over the age of 75, about one-third has sufficient amyloid plaques and neurofibrillary tangles to meet the criteria for Alzheimer’s disease.
These plaques and tangles are especially prominent in those who have Alzheimer’s and contribute to the degradation of neurons in the brain. But they also develop in many elderly people, even those who do not have Alzheimer’s.
It’s these cases — referred to as asymptomatic Alzheimer’s disease (ASYMAD) — that researchers find particularly fascinating. People with ASYMAD have all the physical characteristics that could lead to the progression of Alzheimer’s disease, but have managed to avoid it. If researchers figure out how, then that could lead the way to better, more effective prevention and treatment measures for Alzheimer’s, which are both sorely lacking right now.
Negativity Hurts the Brain
A team of researchers hypothesized that certain personality traits contribute to the cognitive resilience of ASYMAD. They compared the personality traits of those who subsequently developed clinical dementia with those who subsequently died cognitively normal, but with plaques and tangles indicative of Alzheimer’s discovered at autopsy.
And the results of this study may just want to make you turn that frown upside down, especially if you want to protect your brain.
The subjects in this study were also participants in the Baltimore Longitudinal Study of Aging, a study of physical and psychological aging. All agreed to have an autopsy of the brain following their death.
Researchers analyzed data obtained from 111 of the participants who completed personality tests at least once before the onset of cognitive decline, and who underwent autopsies after death.
Personality traits were measured using a 240-item questionnaire that looked at 30 facets of personality, six for each of the five major dimensions of personality: neuroticism, extraversion, openness, conscientiousness and agreeableness.
As for neuropathology, participants were divided into three groups based on their cognitive health in their last year of life and their autopsy results:
1. Normal: Patients had no history of cognitive decline and autopsies showed no amyloid beta plaques or other signs of Alzheimer’s.
2. ASYMAD: Patients had no history of cognitive decline, but the autopsies showed amyloid beta plaques in the brain.
3. AD: Patients received clinical diagnosis of dementia and/or Alzheimer’s disease while alive, and autopsies revealed amyloid beta plaques and other signs indicative of Alzheimer’s.
Looking at the results of the autopsies and the personality questionnaires, researchers discovered that those who had greater emotional resilience and conscientiousness had lower risk of developing dementia, even if their autopsies revealed plaques or other signs of Alzheimer’s.
More specifically, ASYMAD patients scored lower on their personality questionnaires on negative traits like neuroticism, vulnerability to stress, anxiety and depression, compared with controls and to those who actually developed Alzheimer’s disease.
In addition, low scores on conscientiousness were strongly associated with the development of clinical dementia.
Researchers believe those who are more emotionally stable and conscientious may have greater resilience because they are generally healthier and engage in behaviors that reduce the risk of dementia — like exercising and abstaining from tobacco use. In addition, emotionally stable people tend to have better metabolic and inflammatory risk profiles and are less likely to have depression — all of which have been linked to dementia.
Also, they found that personality might be related to the severity of disease. Specifically, high neuroticism and low agreeableness were linked to more advanced spread of tangles. And skepticism, cynicism and being manipulative/deceptive were the characteristics associated with the most severe amyloid plaques and tangles.
This knowledge of how personality traits affect the development of dementia allows us to see just how much of a role attitude plays in our overall health.
The more negative your overall demeanor, the more it will affect your health, possibly leading to cognitive decline and Alzheimer’s disease. Conversely, even if you are at physically high risk of Alzheimer’s, having a positive attitude toward life could delay or stop the progression of the disease. All the more reason to spend as much time as you can smiling, laughing and appreciating all the little things in your life.
 Terracciano A et al. Personality and resilience to Alzheimer’s disease neuropathology: a prospective autopsy study. Neurobiol Aging. 2012 Oct 2. pii: S0197-4580(12)00430-7. doi: 10.1016/j.neurobiolaging.2012.08.008. [Epub ahead of print.]
 Saczynski JS et al. Depressive symptoms and the risk of dementia: the Framingham Heart Study. Neurology. 2010 Jul 6;75(1):35-41.