"There appears to be a dose-response pattern, i.e., the higher the scores the higher the risk of dementia," says Yonas Geda, M.D., a Mayo Clinic neuropsychiatrist and the study's lead investigator.
Dementia is a neurological disorder that affects the ability to think, speak, reason, remember and move. The three most common forms of dementia are Alzheimer's disease, vascular dementia and Lewy body dementia.
Although it's common to see personality changes such as pessimism, depression, agitation or withdrawal once a person develops dementia, the Mayo Clinic investigators believe that pessimism and depression are more likely to be risk factors for dementia rather than early manifestations of the disease due to the significant time gap between the time of the personality test (in the 1960s) and the appearance of dementia or cognitive impairment (anytime between the 1960s and 2004). The test takers ranged in age from 20 to 69 when they took the test in the 1960s.
The Mayo Clinic investigators advise some caution in determining if one's personality traits may predispose to dementia. "One has to be cautious in interpreting a study like this," says Dr. Geda. "One cannot make a leap from group level data to the individual. Certainly the last thing you want to do is to say, 'Well, I am a pessimist; thus, I am doomed to develop dementia 20 or 30 years later,' because this may end up becoming a self-fulfilling prophecy."