Risk factors for Alzheimer’s disease and other dementia-related disorders tend to include age, family history, and genetics, but according to new research, personality could also be a telltale sign of future neurological deterioration. A recent study published in the journal Neurology suggests that middle-aged women dealing with long-term stress and an introverted personality are at a higher risk for developing dementia or Alzheimer’s.

“Our study suggests that midlife neuroticism is associated with increased risk of AD dementia, and that distress mediates this association,” lead researcher Lena Johansson and her colleagues concluded. “The results have clinical implications because a group of women at risk of AD dementia is identified.”

Johansson and her colleagues started assessing the cognitive development of 800 women between the ages of 38 and 54 in 1968. Participants were examined using the Eysenck Personality Inventory at the beginning of the study and assessments were carried out in 1974, 1980, 1992, 2000, and 2005. The research team measured distress via a standardized question during each follow up. In addition to psychiatric examinations, interviews, hospital records, and registry data, DSM-III-R criteria was used to diagnose dementia.

By the end of the 38-year study, 153 women had developed dementia, including 104 who were diagnosed with Alzheimer’s. Women with neurotic tendencies and an introverted personality were at the highest risk for developing dementia. Neurotic women who were under long-term stress also had an increased dementia risk, but that finding depended on the degree of stress. On the other hand, women with an extrovert personality and a lower degree of long-term distress had a very low risk of developing dementia.

“We all have moments when we feel stressed or worried, but stressed women reading this shouldn't take this research to mean they're necessarily at higher risk of dementia,” Dr. Clare Walton, Research Manager at Alzheimer's Society, said in a statement. “This research doesn't show that neuroticism in women alone could increase risk of developing Alzheimer's disease, but what it does suggest is that personality traits like neuroticism are linked to the experience of long term stress.”

According to the Alzheimer’s Association, Alzheimer’s is the most common form of dementia, accounting for 60 to 80 percent of dementia cases. One out of every three senior citizens dies each year as the result of Alzheimer’s or another dementia-related disorder. Around two-thirds of Alzheimer’s patents in the United States are women. A woman’s risk for developing Alzheimer’s in her 60s is one in six, which is significantly higher than breast cancer at one in 11.

“This study adds to the mounting evidence that long term stress contributes to the development of dementia but we need more research to untangle whether personality also plays a role,” Walton added. “While we can't control all the sources of everyday stress, we can develop coping strategies to deal with them, and we're funding research to help explore how this could help with reducing risk of dementia.”

Source: Guo X, Duberstein P, Johannson J, et al. Midlife personality and risk of Alzheimer disease and distress. Neurology. 2014.