New research suggests that people with ADHD may be at increased risk of developing dementia later in life.
Adults with attention deficit hyperactivity disorder (ADHD) could be at an increased risk of developing dementia later in life, according to new research.
ADHD is a neurodevelopmental disorder characterised by inattention, hyperactivity, and impulsivity, but the researchers said evidence supports the existence of adult-onset ADHD.
A team from the Rutgers Brain Health Institute (BHI) analysed records from more than 100,000 older adults in Israel over 17 years, from 2003 to 2020. Then they looked at the occurrence of dementia among them as they aged.
They found that adults diagnosed with ADHD were nearly three times more likely to develop dementia than others. The findings were published in JAMA Network Open journal.
“By determining if adults with ADHD are at higher risk for dementia and if medications and/or lifestyle changes can affect risks, the outcomes of this research can be used to better inform caregivers and clinicians,” said Michal Schnaider Beeri, co-author of the study at the Rutgers BHI in a statement.
Between three and four per cent of English adults have ADHD according to a dedicated charity, with the United States having a similar prevalence rate. Worldwide, millions of adults are affected.
“This study is not able to describe if there is a causal mechanism involved and if so what it is,” said Roxana O Carare, a professor at the University of Southampton, who wasn’t part of the study.
These results represent a “starting point“ to investigate the subject further, she added.
Researchers posited that adult ADHD might manifest as a neurological process that impairs the individual's ability to compensate for cognitive decline in later life.
The study also suggests that ADHD treatment incorporating psychostimulants may help mitigate the risk of dementia in adults with ADHD.
Psychostimulants typically stimulate various neurotransmitters in the brain, particularly dopamine and norepinephrine. They can enhance focus, reduce impulsivity, and manage symptoms of excessive sleepiness.
However, researchers emphasised the need for further studies to delve deeper into the impact of medications on patients with ADHD and their potential influence on dementia risk.
A growing body of evidence
The Rutgers study adds to other research that has found links between ADHD and dementia.
Last year, a study of three million people in Sweden born between 1932 and 1963 similarly found that people with ADHD were nearly three times more likely to develop dementia.
People with ADHD were also six times more likely to develop mild cognitive impairment, the study showed.
In 2021, a study was conducted on two million people born in Sweden between 1980 and 2001. It showed that parents and grandparents of individuals with ADHD were at higher risk of dementia than those with children and grandchildren without ADHD.
These studies were not able to determine a cause-and-effect relationship between ADHD and dementia but rather found links between the two.