Midlife personality and risk of Alzheimer disease and distress: A 38-year follow-up.

OBJECTIVE To study the association between midlife neuroticism and extraversion and development of late-life dementia and long-standing distress in a sample of women followed for 38 years. METHODS A population-based sample of 800 women, aged 38 to 54 years, was examined in 1968, with subsequent examinations in 1974, 1980, 1992, 2000, and 2005. Neuroticism and extraversion were assessed using the Eysenck Personality Inventory at baseline. Distress was measured according to a standardized question at each study wave. Dementia was diagnosed according to DSM-III-R criteria based on information from neuropsychiatric examinations, informant interviews, hospital records, and registry data. RESULTS During the 38-year follow-up, 153 women developed dementia; Alzheimer disease (AD) dementia was diagnosed in 104 of these. A higher degree of neuroticism in midlife was associated with increased risk of AD dementia and long-standing distress over 38 years. The association between neuroticism and AD dementia diminished after adjusting for long-standing distress. Extraversion was associated with a lower degree of long-standing distress, but had no impact on AD dementia. When the 2 personality dimensions were combined, high neuroticism/low extraversion showed the highest risk of AD dementia. CONCLUSIONS Our study suggests that midlife neuroticism is associated with increased risk of AD dementia, and that distress mediates this association. The results have clinical implications because a group of women at risk of AD dementia is identified.