A new US study has found that adults with attention-deficit/hyperactivity disorder (ADHD) face a significantly higher risk of developing dementia or mild cognitive impairment later in life.
The research led by University of Pittsburgh School of Medicine researchers and published in JAMA Psychiatry, also found that people who carry a higher genetic risk for ADHD face a greater chance of cognitive decline even without a documented diagnosis.
The new study is the largest and most comprehensive to date to combine clinical diagnoses and genetic data within the same population. Researchers analysed health records and genetic data from more than 187,000 adults aged 50 and older enrolled in the US National Institutes of Health’s All of Us Research Programme and found that 6.7 per cent of participants with ADHD developed dementia or cognitive impairment, compared with 3.4 per cent of those without ADHD. After accounting for factors like age, sex, and other health conditions, researchers found that people with ADHD had more than four times the risk of developing cognitive impairment over time.
The researchers also calculated each participant’s genetic risk score for ADHD, a measure that reflects how much a person’s common genetic variants are associated with ADHD, regardless of whether they were ever formally diagnosed. People with the highest genetic risk had a 35 per cent greater chance of developing dementia than those with the lowest risk.
“This doesn’t prove that ADHD causes dementia, but seeing the same pattern show up independently in medical records and in people’s genes gives us greater confidence that the association is not simply an artifact of how ADHD gets diagnosed,” said senior author Dr Tharick A Pascoal, Associate Professor of Psychiatry and Neurology, University of Pittsburgh School of Medicine, US. “Two different kinds of evidence are pointing in the same direction.”
The study also found that ADHD compounded the burden of living with dementia. Among participants who developed cognitive impairment, those with a comorbid ADHD diagnosis reported worse mental health, lower quality-of-life and less social satisfaction than those with dementia alone. They also used about 20 per cent more healthcare overall in the year following diagnosis.
“We’re replicating a pattern that’s been observed in other countries, now in a large US sample, and adding genetic evidence on top of it,” said Dr Douglas Teixiera Leffa, who recently completed his psychiatry residency at University of Pittsburgh Medical Centre.
“That combination gives us more confidence that ADHD deserves a closer look as a potential factor in cognitive ageing.”
One possibility is that early, undetected dementia symptoms are sometimes mistaken for ADHD before a formal cognitive diagnosis is made. However, the association remained statistically significant even when the team required at least eight years to pass between an ADHD diagnosis and the onset of cognitive impairment, making that explanation less likely to account for the full effect.
The findings align with and expand a growing literature supporting an association between ADHD and increased risk of mild cognitive impairment and dementia. Studies using population-based health claims databases from Taiwan, Sweden, Israel, and Germany have reported elevated risk estimates that are broadly comparable in magnitude to this study, indicating that the association is not confined to a single healthcare setting or diagnostic context. The findings also build on years of related work from the University of Pittsburgh School of Medicine’s Pascoal lab, including a 2022 study that first linked ADHD genetic risk to Alzheimer’s-related brain changes in cognitively unimpaired older adults.
However, several questions remain unanswered, including whether ADHD medications, such as stimulants, might lower dementia risk over time, and whether managing cardiovascular health – already linked to both ADHD and dementia – could help.
Reference
- Bauer-Negrini G, Leffa DT, Ferreira PCL, Bellaver B, Povala G, Medeiros MS, et al. Attention-deficit/hyperactivity disorder and late-life cognitive impairment. JAMA Psychiatry. 2026 Oct 7
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