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ADHD Linked to Fourfold Higher Dementia Risk in Large Study
A University of Pittsburgh study of more than 187,000 adults finds ADHD associated with a substantially increased risk of dementia and mild cognitive impairment, though researchers caution the findings show only a correlation.
Adults with attention deficit hyperactivity disorder face more than four times the risk of developing dementia or mild cognitive impairment compared with those without the condition, according to a new study led by the University of Pittsburgh School of Medicine.
The observational research, published Oct. 7 in JAMA Psychiatry, examined the electronic health records and genetic information of more than 187,000 adults aged 50 and older enrolled in the National Institutes of Health All of Us Research Program. Cognitive impairment was observed in 6.7% of participants with ADHD versus 3.4% of those without the disorder, nearly double the rate. After researchers adjusted for age, gender and other health conditions, the ADHD group's risk rose to more than four times that of the comparison group.
The study also found that participants with the highest genetic susceptibility to ADHD had a 35% greater risk of dementia than those with the lowest susceptibility. Researchers said the convergence of two independent types of evidence — medical records and genetic data — strengthens confidence that the association is not merely an artifact of how ADHD is diagnosed.
«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 Tharick A. Pascoal, associate professor of psychiatry and neurology at Pitt. «Two different kinds of evidence are pointing in the same direction.»
Guilherme Bauer-Negrini, co-first author and postdoctoral associate in biomedical data science at Pitt, said analyzing genetic information alongside years of health records allows researchers to identify patterns that might not be visible in smaller or more traditional studies. He said the approach could help investigators determine what may be driving the association and whether any factors could be modified to support healthier cognitive aging.
Dr. Elizabeth Landsverk, a California-based geriatric medicine and dementia expert not involved in the study, said people with ADHD can have more difficulty with organization, which could contribute to higher rates of cognitive impairment. She noted that the study found people with ADHD had a 20% higher incidence of utilizing health resources.
«Having just signed up for Medicare, I know that it's really complicated — if you have trouble with focusing and getting things done, you may not be able to get the resources that you need,» Landsverk said. «You may not be able to go to the doctor. You may not get your blood pressure taken care of. So there's probably a correlation.»
She described the relationship as a question of nature versus nurture, particularly when studying adults from age 50 onward rather than from age 20. Distinguishing between ADHD and cognitive decline can be challenging because some symptoms overlap, she added, noting that forgetting why you entered a room or where you left your keys can occur in both conditions.
Landsverk said it is cause for concern when a person struggles with day-to-day tasks such as paying bills, managing medications or keeping appointments. Changes in judgment, mood or social behavior may be more suggestive of dementia than ADHD, she said, and anyone experiencing persistent problems with memory, focus, organization or daily tasks should consider an evaluation.
Despite the findings, Landsverk emphasized that several lifestyle behaviors can help reduce overall dementia risk. She pointed to maintaining a healthy weight, avoiding smoking and excessive alcohol, staying physically active, and controlling blood pressure, cholesterol and diabetes as important modifiable factors. She recommended a largely plant-based diet and at least 30 minutes of daily exercise, noting that physical activity can also improve mood and focus.
The researchers acknowledged that the study's observational design means it cannot determine that ADHD increases dementia risk, only that the two are associated. They said further work is needed to investigate potential mechanisms behind the link and whether any of the factors involved could be modified to support healthier cognitive aging.
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