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People who are often stressed or depressed are far more likely to develop memory problems than those with sunnier dispositions, according to researchers in the United States.
The finding sheds light on early predictors of Alzheimer's disease. Those who most often are anxious or depressed were 40 times more likely to develop mild cognitive impairment, a form of memory loss that is often a transitional stage between normal ageing and dementia, according to the research.
"Not only are these individuals losing cognition, but they are showing many of the changes in the brain that are associated with Alzheimer's disease," said Robert Wilson of Rush University Medical Centre in Chicago.
"We now see that chronic distress is related to the first clinical manifestation of Alzheimer's disease."
People with mild cognitive impairment have some trouble remembering things, but they do not have significant disability. Not all develop Alzheimer's disease, a much more serious impairment, but about 10 to 15 per cent do, according to the Alzheimer's Society.
Wilson and colleagues analysed data from two large studies involving 1256 older people who started the studies with no memory problems.
After up to 12 years of follow-up, 482 developed mild cognitive impairment. Participants were rated on how prone they are to worry and depression.
"What we're measuring is a personality trait that we all have to greater or lesser degree. We all experience anxiety and periodic depression. This trait helps identify people for whom that is more characteristic than others," said Wilson, whose study appears in this week's issue of the journal Neurology.
"This isn't a measure of stress, but of the response to stress," he said. The research suggests that chronic stress may harm parts of the brain responsible for responding to stress - an area also associated with memory, he said. The research might lead to early treatments, such as promoting exercise to reduce stress or drug therapy for depression.
- REUTERS
