Frequent "bad dreams" in middle age could be a sign of dementia "several years or decades before a clinical diagnosis" or memory problems, according to new research.
Most people experience distressing dreams at some point, but only 5% of adults suffer nightmares bad enough to break their sleep at least once a week, with more experiencing them monthly. In recent years, researchers have paid more attention to the link between nightmares and cognitive decline, such as in people with Parkinson's disease.
But the authors of a paper published in The Lancet medical journal, eClinicalMedicine, this month say it's surprising the "clinical significance [of nightmares] remains largely unknown". Although "distressing dreams remain relatively stable throughout early adulthood" before increasing in prevalence from middle age, their study found older are twice who experience bad dreams on a weekly basis are twice as likely to be diagnosed with dementia.
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Middle aged people, between 35 and 64, who have them weekly are four times more likely to be experience cognitive decline, according to the research. The link was stronger in men than in women. To find these results, researchers examined data from three previous studies, which looked at more than 600 adults between 35 and 64, and 2,600 aged 79 and older, and followed their progress for several years. All were dementia-free at the start of the study.
The new study's lead author, Dr Abidemi Otaiku of the University of Birmingham, said: "We've demonstrated for the first time that distressing dreams, or nightmares, can be linked to dementia risk and cognitive decline among healthy adults in the general population.
"This is important because there are very few risk indicators for dementia that can be identified as early as middle age. While more work needs to be done to confirm these links, we believe bad dreams could be a useful way to identify individuals at high risk of developing dementia, and put in place strategies to slow down the onset of disease."
A relationship between nightmares could be down to the long-term impact of poor quality sleep - people suffering nightmares "tended to be more depressed, more anxious, and had more sleep problems". But Dr Otaiku suspects the a result of neurodegeneration in the brain's right frontal lobe causing difficulty controlling emotions, making it possible one of the earliest signs of dementia.
Dr Otaiku said the study's results suggest "screening for distressing dreams in the general population may help to identify individuals in the earliest stages of a neurodegenerative dementia". A survey by Alzheimer's Society, the UK's leading dementia charity, found nine in 10 people with dementia - of which there are roughly 900,000 in the country - say they benefitted from getting a dementia diagnosis.
This comes in the form of a better understanding of the changes dementia causes to their mood and behaviour, protection from discrimination and access to state benefits, access to treatment to help them continue living independently, along with support from dementia advisers, support workers and peer groups through the Alzheimer's Society.
Lali Kelly, an Alzheimer's Society dementia support worker in Merseyside, said: "I help people to understand and comes to terms with a diagnosis of dementia, access support and plan for the future. We're here for anyone affected by dementia. We provide practical advice, emotional support, and guidance for the best next step."
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