Increased risk of dementia with night terrors

According to the World Health Organization (WHO), over 50 million people worldwide have dementia today. By 2050, this number is expected to surpass 131 million.

In most cases, dementia is connected to Alzheimer's disease.

Unfortunately, its symptoms often go unnoticed until they become too severe to treat. If left untreated, Alzheimer's disease (AD) can eventually result in death, but early detection and treatment could help prevent or slow down the progression of this awful disease.


New research published in The Lancet shows that those who experience frequent night terrors are at greater risk for developing dementia disease later in life.

The prevalence of dementia has increased with life expectancy, more than one-third of individuals over 80 are likely to develop dementia.

Approximately 5% of adults experience nightmares weekly, becoming more frequent with advancing age.

A study saw that distressing dreams become more common years or even decades before thoughtful, and memory problems set in.

People who had weekly nightmares from 34 to 64 years were four times more likely to suffer cognitive decline over the following ten years.

People aged 79 and over were twice as likely to be diagnosed with dementia if they also had recurring bad dreams, with the link strongest in men.

We've shown for the first time that disturbing dreams, or nightmares, may increase the risk of developing Alzheimer's disease and cognitive decline later in life.  Because there are so few risk factors for Alzheimer's that can be detected before people reach their 50s, we could now consider that dream disturbances could be one of them.

While further study is needed to confirm these links, we believe that nightmares may be an effective method for identifying people likely to develop Alzheimer's disease and putting strategies to slow down its development in place.

Outline of study

The cohort study examined data from three groups of people in the US.

At the beginning of the study, all participants were free of dementia and Parkinson's disease and were tested for episodic memory impairment.  Afterwards, they were asked about their sleep quality, and these measures were compared with test scores indicating their cognitive function.

Those with frequent nightmares were five times more likely to acquire Alzheimer's disease than those without them.  In females, the increased risk was reduced to 41%. They predicted a strong association between cognitive decline and dementia among men.

If somebody can graphically remember their dreams, it might indicate they are at risk.

What if we could spot dementia before symptoms started?  The hope is to recognise the disease before the cognitive deficits have reached the prodromal stage of dementia, before irreversible brain damage or mental decline has occurred.  

If mild cognitive symptoms appear, and they do not interfere with daily activities, this may be tricky to distinguish between normal ageing or dementia.

However, these findings align with several recent investigations that showed disturbing nightmares also predict faster cognitive decline and dementia in people with Parkinson's.

However, this association is not just specific to individuals with Parkinson's disease and can be inferred to the general population.  Therefore, identifying individuals at risk of dementia could facilitate early prevention strategies for both groups.  Among patients with cognitive impairment, Approximately, 80% in primary care will have Alzheimer's disease. 

Unfortunately, early markers now aren't early enough

Early identification of Alzheimer's disease relies mainly on documenting mental decline, at which point Alzheimer's has already caused severe brain impairment.  Investigators hope to discover an easy and low-cost solution to accurately detect Alzheimer's before those devastating symptoms start.

Studies include biomarkers in the blood or urine.  In particular, researchers are looking at specific protein fragments called amyloid beta peptides (Aβ).  These proteins restrict the communication between nerve cells, eventually affecting memory. 

Biomarkers could be measured before and after symptoms appear.  Still, there's no scientific proof that these proteins cause Alzheimer's, and this system has not been validated to accurately measure the disease's presence.

Structural brain imaging, which also uses magnetic resonance imaging (MRI) and positron-emission tomography (PET) scans, is among the most active areas of research aimed at finding new approaches to diagnose Alzheimer's in its earliest stages.

Genetic profiling may become a valuable risk assessment tool.  It has identified three genes that may cause the disease and several genes that increase the risk but don't guarantee that a person will develop Alzheimer's.

Because Alzheimer's disease is already symptomatic long before dementia, there is a necessity today to improve the diagnosis of Alzheimer's to reach a diagnosis earlier, with current drug development aimed at slowing its overall progression.

Patients and caregivers are also reluctant to report signs or symptoms due to the stigma surrounding Alzheimer's.

In conclusion, this investigation was the first to explore the association between distressing dreams in older adults and the subsequent development of clinical dementia.

Nevertheless, previous studies have also established that frequent nightmares were significantly more common among patients with different dementia syndromes.