People with ADHD may be up to four times more likely to develop memory problems in later life compared to those without the disorder, a major study has found.
Researchers suggested this could be because ADHD patients are more likely to eat unhealthy diets and do little exercise – known risk factors for conditions affecting memory, including dementia.
The scientists, from the University of Pittsburgh, tracked 187,341 older adults over ten years, 3,026 of whom had an ADHD diagnosis.
While 3.4 per cent of those without the attention disorder developed memory problems – defined as either a dementia diagnosis or mild cognitive impairment – the prevalence was nearly twice this in people with ADHD, at 6.7 per cent.
However, when the scientists conducted a more in-depth analysis to account for age differences between the groups, they saw the increased risk double to four-fold.
When looking only at those with dementia diagnoses, the increased risk was three-fold.
While mild cognitive impairment can be a precursor to the disease, it is not always. It is a term used to describe problems with memory and thinking that aren’t severe enough to warrant a diagnosis.
People with ADHD may be up to four times more likely to develop dementia or memory problems in later life than those without the disorder, a major study claims
Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP.
The three-fold risk held true even after scientists adjusted for other factors that could explain the link, like physical and mental health conditions, education levels, smoking, and healthcare use.
The study is not the first to link ADHD and dementia.
Separate research published in 2023 in the journal JAMA Network Open also found that adults diagnosed with ADHD had an almost three-times greater risk of developing dementia.
Investigations into what links the two are ongoing, but writing in the journal JAMA Psychiatry, the authors of the new study offered various theories.
One, they said, is that ADHD may be linked to lower ‘cognitive reserve’ – the brain’s ability to complete tasks, particularly after ageing – due to the disorder’s impact on memory and focus.
‘A second hypothesis,’ the authors continued, ‘is that ADHD increases exposure to cumulative risk factors for cognitive impairment’.
These included chronic stress, sleep problems, physical inactivity, poor diet, risk of heart problems and substance use.
Crucially, the study was observational, meaning it cannot prove ADHD itself causes dementia.
The researchers also stressed that some ADHD diagnoses could have reflected early, unrecognised symptoms of cognitive decline.
But, they said their findings ‘support ADHD as a relevant factor in later-life cognitive health’.
A connection between physical and brain health has long existed.
A healthy lifestyle is known to reduce the risk of developing dementia in later life, according to the NHS.
This includes eating a balanced diet, exercising, maintaining a healthy weight, not smoking, keeping blood pressure at healthy levels, and not drinking alcohol excessively.
Almost one million Britons are living with dementia, which claims 76,000 lives a year as Britain’s biggest killer.
The Daily Mail and Alzheimer’s Society have partnered in a drive to defeat dementia with its Defeating Dementia Campaign, which aims to increase early diagnosis, boost research and improve care.
Around 2.5 million people in England are believed to have ADHD, including about 741,000 children and young people aged five to 24.
Diagnoses of the disorder have risen 20-fold over two decades, figures show.
