Adults diagnosed with attention deficit hyperactivity disorder may face a higher risk of developing dementia later in life, according to new research from Geneva University Hospitals and the University of Geneva. The study links ADHD to biological changes often seen in age-related neurodegenerative disease.
Researchers reported that adults with ADHD showed altered iron levels in specific brain regions and higher concentrations of a blood marker tied to nerve cell damage. Both signals have been associated in previous research with conditions such as Alzheimer’s disease.
Brain iron and nerve damage marker
The team examined 32 adults aged 25 to 45 with ADHD and 29 similarly aged healthy participants. Using an MRI technique called quantitative susceptibility mapping, they estimated iron content across brain areas and compared it with blood measurements.
Participants with ADHD had different iron distribution in several regions, and iron in the precentral cortex was associated with higher neurofilament light chain levels in blood. Neurofilament light chain is widely used in neurology research as an indicator of ongoing neuronal injury.
Why iron may matter
Iron is essential for healthy brain function, but excess accumulation has been linked to oxidative stress and damage to neurons. In Alzheimer’s disease and other dementias, abnormal iron patterns have repeatedly been observed alongside other signs of degeneration.
The authors argue that the combination of increased regional brain iron and elevated neurofilament light chain could point to an early neurobiological pathway that helps explain epidemiological links between ADHD and dementia. They emphasize, however, that the findings do not mean dementia is inevitable for people with ADHD.
What this could change next
With dementia affecting an estimated 55 million people worldwide and nearly 10 million new cases each year, identifying modifiable risks remains a major public health goal. Alzheimer’s disease accounts for roughly 60 to 70% of diagnoses, according to the World Health Organization.
The researchers say larger, long-term studies are needed to confirm whether these markers predict later cognitive decline and whether interventions can alter risk. They also note the broader importance of recognizing and managing adult ADHD, both for day-to-day functioning and potential long-term brain health.
