Ongoing research suggests stress might play a part in dementia
People who have mild cognitive impairment are at an increased risk of going on to develop dementia - although some will remain stable and others may improve.
And past work suggests mid-life stress may increase a person's risk of Alzheimer's disease.
A Swedish study that followed nearly 1,500 women for a period of 35 years found the risk of dementia was about 65% higher in women who reported repeated periods of stress in middle age than in those who did not.
Scottish scientists, who have done studies in animals, believe the link may be down to hormones the body releases in response to stress which interfere with brain function.