Adults with attention deficit hyperactivity disorder (ADHD) are almost three times more likely to develop dementia than those without the condition, according to a new study. It highlights the need for more attention to be paid to a group that has historically been excluded from this kind of research.

For many years, ADHD was considered almost exclusively in the context of children. Nowadays, more and more adults are being diagnosed, and the different presentations of the condition in previously understudied groups – mainly women and girls – are being recognized. It’s now estimated that 3 percent of the adult population has ADHD.

However, one group that remains poorly understood is older adults. 

“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, director of the Herbert and Jacqueline Krieger Klein Alzheimer’s Research Center at Rutgers Brain Health Institute, in a statement.   

Beeri is co-author of a new study that sought to do just that, by analyzing data from over 100,000 people enrolled in a national cohort study in Israel. The study period ran from 2003 to 2020, and the researchers compared the incidence of dementia between participants with and without an ADHD diagnosis. 

The study found that ADHD was significantly associated with an increased risk of dementia. This remained true even when other contributing risk factors, such as cardiovascular disease, were taken into account. The risk of dementia was found to be almost 3-fold higher in those with ADHD.

This is an important finding, which chimes with some – but not all – of the previous work in this area. The authors speculated that the brains of adults with ADHD may be less able to compensate for the effects of aging, making them more susceptible to dementia. They also note that symptoms of ADHD in older people should be taken seriously, as they can mirror some of the earliest signs of cognitive decline.

“Physicians, clinicians and caregivers who work with older adults should monitor ADHD symptoms and associated medications,” said senior author Abraham Reichenberg of the Icahn School of Medicine at Mount Sinai.

“Symptoms of attention deficit and hyperactivity in old age shouldn’t be ignored and should be discussed with physicians,” added Stephen Levine, from the University of Haifa’s School of Public Health.

The results of the study also raise intriguing questions about the effects of psychostimulant drugs used to treat ADHD. The names of some of these, such as Ritalin (methylphenidate) and Adderall (amphetamine/dextroamphetamine), will be familiar to many. The study found that these treatments could potentially help mitigate the increased risk of dementia, but that further work was needed to analyze the risks and potential benefits in more depth.

Dementia is already a huge concern for health authorities the world over. Interest in and awareness of ADHD has exploded in recent times, but there is still some way to go to redress the balance in academic research, to ensure that adults with ADHD continue to receive high-quality, tailored medical interventions throughout their lifetimes.

The study is published in the journal JAMA Network Open.