According to a new study people who are laid back and outgoing have a 50 % lower risk of developing Alzheimer’s disease in their old age. The study published in the journal Neurology also suggests that people who are anxious, timid, shy or prone to getting stressed are more likely to develop dementia in their later years.

Researchers asked 506 people who were aged 78 or more to fill in a questionnaire which helped assess their personalities and lifestyles. The lifestyle questionnaire asked them how often they participated in leisure activities and measured how socially active they were. The questionnaire also measured neuroticism  or how easily distressed the subjects were prone to becoming.

They were followed for six years  and the researchers found that 144 by then had developed Alzheimer’s or other forms of dementia. The researchers found that people who were not easily distressed were people who were calm and self satisfied and had a 50 % lower risk of developing dementia. The participants who were distressed were emotionally unstable, negative and nervous and were 50 % more likely to develop Alzheimer’s or dementia as compared to the calmer group.

Dr Hui-Xin Wang, of the Karolinska Institute in Sweden who led the study said it was not yet clear how mental attitude influences dementia risk. "In the past, studies have shown that chronic distress can affect parts of the brain, such as the hippocampus, possibly leading to dementia. But our findings suggest that having a calm and outgoing personality in combination with a socially active lifestyle may decrease the risk of developing dementia even further.

"The good news is, lifestyle factors can be modified as opposed to genetic factors which cannot be controlled. But these are early results, so how exactly mental attitude influences risk for dementia is not clear."

One theory that experts propound is that stress and anxiety trigger the release of chemicals which can damage the tissues of the brain. UK experts said the study offered "compelling evidence" of the need to be "socially active throughout life".

Dr Susanne Sorensen, head of research at the Alzheimer's Society, said, "Doctors have always believed that personality traits are linked to risk of dementia. This compelling new evidence suggests people who are easily stressed or not very outgoing should make every effort to be socially active."

Previous research has indicated that risk of dementia and mental decline increases with social isolation and a study conducted in the U.S. last year showed a distinct link between feelings of loneliness and the chances of suffering Alzheimer’s being intertwined.

Sorensen said, "It's a chicken and egg scenario - do these personality traits increase risk of dementia in older people or are they an early sign of the disease”?

Alzheimer’s disease has no cure although new drugs can delay the progress of devastating symptoms such as memory loss and erosion of the ability to do everyday things.

Sorensen concluded, "One in three people over 65 will die with dementia. It is vital to keep mentally and physically active throughout your life to reduce risk of this devastating condition."