Effects of stress on the brain could trigger Alzheimer's

Researchers at the University of Edinburgh have identified for the first time a certain area of the brain which can shrink in old age and cause depression and Alzheimer's disease.

The scientists say when that area is damaged by stress hormones, it can trigger dementia.

For the study the scientists analysed stress hormone levels and brain volume in two groups of ten healthy male volunteers aged 65-70 for the study.

The team examined the size of a special region of the brain, the anterior cingulate cortex, thought to be involved in controlling stress hormones.

Lead author Dr Alasdair MacLullich says doctors have known for years that ageing, and certain diseases common in ageing, such as Alzheimer's disease and depression, can be associated with shrinkage of the brain.

He says they made a significant discovery when they found that people with a smaller anterior cingulate cortex had higher levels of stress hormones.

High levels of stress hormone have been found to shrink the anterior cingulate cortex at the centre of the brain.

The researchers say brain scans showing a shrunken cingulate indicates the potential for Alzheimer's to develop in the future.

The researchers say the discovery deepens doctors' understand of ageing, depression and Alzheimer's diseases, and will help in the development of treatments based on reducing high levels of stress hormones.

The study is published in the current on-line edition of The Journal of Clinical Endocrinology and Metabolism.