Adult ADHD Tied to a 4.6-Fold Higher Risk of Late-Life Cognitive Decline

Adult ADHD Tied to a 4.6-Fold Higher Risk of Late-Life Cognitive Decline

187,000 Adults, About a Decade of Records

Researchers at the University of Pittsburgh School of Medicine analyzed health records and genetic data from 187,341 adults aged 50 and older enrolled in the National Institutes of Health's All of Us Research Program. None had cognitive impairment at baseline, and about 1.6 percent — 3,026 people — carried an ADHD diagnosis in their records. Over roughly a decade of follow-up, 6.7 percent of the ADHD group, 203 people, were diagnosed with mild cognitive impairment or dementia, compared with 3.4 percent of everyone else, 6,259 people. The paper was published online October 7 in JAMA Psychiatry.

The Signal Survived Every Adjustment

After accounting for sex, race, ethnicity, APOE epsilon 4 status and the year of cohort entry, ADHD was associated with a 4.6-fold higher hazard of cognitive impairment (HR 4.60, 95% CI 3.99-5.29, P<.001). Adding comorbid physical illnesses, educational attainment and how often participants saw a doctor brought the figure to 4.04; folding in mental health conditions still left it at 3.19. Restricted to dementia alone, the hazard ratio was 3.07 (95% CI 2.12-4.44), and 3.83 when only mild cognitive impairment was counted.

Genetic Scores Point the Same Direction

The team also built an ADHD polygenic risk score from common genetic variants. People in the highest quintile had a 35 percent higher hazard of developing cognitive impairment than those in the lowest quintile (HR 1.35, 95% CI 1.25-1.46, P<.001), an association that persisted after adjustment for medical and psychiatric comorbidities and that showed up even among participants never clinically diagnosed with ADHD. "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 Tharick Pascoal, the study's senior author.

A Heavier Burden Once Impairment Hits

Among participants who did develop cognitive impairment, a comorbid ADHD diagnosis came with worse mental health (OR 1.69), lower quality of life (OR 1.66) and lower social satisfaction (OR 2.39), along with about 20 percent higher health care use in the year after diagnosis (IRR 1.20). The added burden showed up as a care problem, not only a diagnostic one.

Researchers Stop Short of Causation

Pascoal cautioned that the findings do not establish that ADHD causes dementia. The authors flagged residual confounding, reverse causation given the long prodromal phase of dementia, and selection bias in a volunteer cohort such as All of Us. An Israeli study suggested that adults diagnosed with ADHD late in life and treated with stimulants did not have an elevated dementia risk, though the researchers said confounding could not be ruled out. Because lifetime treatment data are limited, whether treating ADHD alters dementia risk remains unanswered.

What Might Be Doing the Driving

Douglas Teixeira Leffa, an investigator on the study, said the explanation likely involves multiple interacting processes, including greater lifetime exposure to sleep problems, cardiometabolic risk, physical inactivity, substance use, chronic stress and social adversity. Elizabeth Landsverk, a geriatrician not involved in the work, pointed to the day-to-day side: people with ADHD may struggle more with organization and with keeping up with their own care. "It might be that keeping on top of health issues and getting to the doctor is more difficult for them," she said. Leffa urged restraint, saying people with ADHD should not read the results as a prediction that they will develop dementia.

Who Should Pay Attention, and What Comes Next

A 2023 CDC survey estimated that 6.0 percent of US adults, about 15.5 million people, report a current ADHD diagnosis, and 55.9 percent of them were first diagnosed at age 18 or older. The authors called for cognitive monitoring in adults with ADHD and for further research into the underlying mechanisms and whether the association is causal. Greg Fabiano, a psychology professor at Florida International University, told Newsweek the findings add to the accumulating evidence that ADHD is a risk factor for challenging outcomes across development, up to and including later adulthood.