Mid-life stress raises risk of dementia later in life

A new study has revealed that stress due to common life events may cause a number of physiological reactions in the central nervous, endocrine, immune and cardiovascular systems, and it may trigger long lasting physiological changes in the brain.

Researchers base their findings on 800 Swedish women whose mental health and wellbeing was formally tracked over a period of almost 40 years as part of the larger Prospective Population Study of Women in Gothenburg, Sweden, which started in 1968.

The women, who were all born in 1914, 1918, 1922 and 1930, underwent a battery of neuropsychiatric tests and examinations in 1968, when they were in their late 30s, mid 40s, and 50s, and then again in 1974, 1980, 1992, 2000 and 2005.

At their initial assessment, the women were quizzed about the psychological impact on them of 18 common stressors, such as divorce, widowhood, serious illness or death of a child, mental illness or alcoholism in a close family member, personal or partner's unemployment, and poor social support.

In 1968 one in four of the women had experienced at least one stressful event; a similar proportion had experienced at least two, while one in five had experienced at least three, and 16 percent four or more. The most commonly reported stressor was mental illness in a close family member.

The number of stressors reported by the women was associated with longstanding symptoms of distress at all of the time points assessed, irrespective of the year of birth and the number of stressors reported in 1968 was associated with a 21 percent heightened risk of developing Alzheimer's disease and a 15 percent heightened risk of developing any type of dementia.

The findings held true even after taking account of factors likely to influence the results, including a family history of mental health problems.