Women who experience anxiety, jealousy or are moody and distressed during middle age may have a higher risk of developing Alzheimer’s disease in later life, new research suggests.
The study of 800 women found that having particular personality traits was linked to a greater chance of developing Alzheimer’s.
It is thought these traits may increase dementia risks due to their effects on how people live their lives and how they react to stress. Previous research has linked chronic stress to an increased risk of dementia.
Campaigners called for bigger trials to see whether tackling stress could help reduce cases of Alzheimer’s in later life.
In Scotland, around 88,000 people are estimated to have dementia.
The latest study, published in the journal Neurology, followed 800 women with an average age of 46 for 38 years.
The women were given personality tests that looked at their levels of neuroticism and extraversion or introversion, along with tests of their memory.
Of the women taking part in the study, 19 per cent went on to develop dementia.
The researchers, from the University of Gothenberg in Sweden, said neuroticism involved being easily distressed and having personality traits such as worrying, jealousy or moodiness.
They said that people who were neurotic were more likely to express anger, guilt, envy, anxiety or depression, while introversion was described as shyness and reserve and extraversion being outgoing.
The participants were also asked if they had experienced any period of stress that lasted one month or longer in their work, health or family life, including feelings such as tension, nervousness, fear, anxiety or sleep disturbances.
The women were given a score of zero to five, with zero representing no stress to five being constant stress. Those scoring between three and five were considered to have suffered distress.
The researchers found that women who scored the highest on tests for neuroticism had double risk of developing dementia compared to those who scored lowest on the tests, with the link depending on experiencing long-term stress.
The study said that being either withdrawn or outgoing did not appear to raise dementia risk alone, but women who were both easily distressed and withdrawn had the highest risk of Alzheimer’s in the study.
The researchers found that 16 of the 63 women (25 per cent) who were easily distressed and withdrawn developed Alzheimer’s. In comparison, eight out of 64 people (13 per cent) who were not easily distressed and were outgoing developed the disease.
Lead researcher Lena Johannsson said: “Most Alzheimer’s research has been devoted to factors such as education, heart and blood risk factors, head trauma, family history and genetics.
“Personality may influence the individual’s risk for dementia through its effect on behaviour, lifestyle or reactions to stress.”
Dr Simon Ridley, head of research at Alzheimer’s Research UK, said studies like this could be important for picking out health trends, but were not able to pin down cause and effect, though they added to a body of existing stress evidence.