Carried out by scientists from the University of Geneva (UNIGE) and the University Hospitals of Geneva (HUG), Switzerland, the new study looked at 65 participants over the age of 65 and followed them for a period of five years.
During this time, the participants underwent tests such as neurocognitive assessments, functional and structural brain imaging to assess amyloid accumulation in the brain and brain volume, and personality tests.
The findings, published in the journal Neurobiology of Aging, showed perhaps surprisingly, that people who score lower for agreeableness — in short people who are more unpleasant — appeared to have a brain that is better protected against Alzheimer’s disease. The same was also true for people who are not afraid of conflicts and who show characteristics of anti-conformity.
Participants with these three personality traits tended to lose less volume in the brain regions which typically shrink in both normal aging and in Alzheimer’s disease.
The researchers explain that atrophy, or shrinking, of certain brain regions is one of the major features that comes before memory loss and Alzheimer’s disease.
“A high level of agreeableness characterizes highly adaptive personalities, who want above all to be in line with the wishes of others, to avoid conflict, and to seek cooperation,” explains Professor Panteleimon Giannakopoulos, who directed the research. “This differs from extraversion. You can be very extroverted and not very pleasant, as are narcissistic personalities, for example. The important determinant is the relationship to the other: do we adapt to others at our own expenses?”
In addition, the team also found that another personality trait that seems to have a protective effect is being curious and open to experience. “This is less surprising, as we already knew that the desire to learn and interest in the world around us protects against cerebral ageing,” said Professor Giannakopoulos.
Alzheimer’s is the main cause of dementia in the elderly. Some risk factors for the disease have already been established, such as high blood pressure or diabetes, but the how non-biological factors may play a role is still unclear.
“If it seems difficult to profoundly change one’s personality, especially at an advanced age, taking this into account in a personalized medicine perspective is essential in order to weigh up all the protective and risk factors of Alzheimer’s disease. It is an important part of a complex puzzle,” the authors conclude.