People who have experienced post-traumatic stress disorder (PTSD) are up to twice as likely to develop dementia later in life, according to a new study.
Researchers compared people in the general population with a PTSD diagnosis with veterans who’d experienced PTSD. The research indicated that the dementia risk was higher in those who weren’t veterans.
The team suggest this may point to an effect of treating PTSD, as veterans are more likely to receive treatment for the condition. They suggest that treating PTSD may reduce subsequent dementia risk.
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Researchers analysed the results of 13 studies conducted on four continents – including data from 1,693,678 people – that looked at whether a PTSD diagnosis was associated with increased risk of dementia up to 17 years later.
By pooling data from eight of the studies, the scientists found that people with PTSD faced a 61 per cent higher risk of dementia.
Analysing data from two other studies that used different methods, they found the condition was associated with double the odds of developing dementia.
Senior author Dr Vasiliki Orgeta, from University College London’s Psychiatry division, said: “Our study provides important new evidence of how traumatic experiences can impact brain health, and how the long-term effects of trauma may impact the brain in many ways increasing vulnerability to cognitive decline and dementia.
“A lot of people with PTSD don’t access treatment, sometimes due to a lack of mental health care capacity but also because of stigma which often keeps people away from seeking help.
“We now have more evidence of how traumatic experiences and accessing treatment could have a long-lasting impact for individuals and influence future risk of developing dementia.”
Researchers say the risk could be higher than the studies suggest, as PTSD also increases the likelihood of developing other known dementia risk factors, such as depression, social isolation, or elevated alcohol intake.
These were factors that most of the studies adjusted for.
The study published in the British Journal of Psychiatry suggests it remains unclear how PTSD raises dementia risk.
But the researchers say it may be related to hypervigilance and recurrent re-experiencing of trauma, contributing to threat and stress-related activity in the brain, while withdrawal from social life may reduce cognitive reserve and resilience.
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The study’s first author, Mia Maria Günak commented: “Our findings add to a growing body of evidence that dementia can sometimes be prevented by addressing risk factors throughout an individual’s life course. Here we have identified an additional group of people who face an elevated risk of dementia, who may benefit from further mental health support.”
Dr Orgeta added: “PTSD, which appears to be common among people who have been hospitalised with COVID-19, remains an under-diagnosed, under-treated, and under-researched mental health condition, yet it can have serious long-term consequences.
“As our study has shown, PTSD impacts our brain health by increasing vulnerability to dementia. An important question is how, and whether we could learn from these findings to develop preventative treatments for those with elevated risk.”
The researchers were supported by the NIHR University College London Hospitals Biomedical Research Centre and the Alzheimer’s Society.
What is dementia?
Some 850,000 people are estimated to be living with dementia in the UK, and that’s expected to rise to two million by 2050. Most of us probably know, or have known, someone with dementia. But we may not understand the difference between dementia and, say, Alzheimer’s disease.
Dementia describes the symptoms that someone experiences as a result of a brain disease. Such symptoms can include memory loss, mood and behavioural changes, and difficulties with thinking, problem-solving and language.
More than 100 diseases can cause dementia, each with slightly different symptoms. The most common cause of dementia is Alzheimer’s.