ADHD Dementia Risk Four Times Higher in Large Study

Adults with ADHD face a sharply higher risk of memory problems later in life, according to a large new study. Researchers at the University of Pittsburgh School of Medicine analyzed health records from 187,341 adults aged 50 and older enrolled in a large National Institutes of Health research program that combines health records with genetic data. The work, published in JAMA Psychiatry, is the largest study to date of ADHD dementia risk, and it combined electronic health record diagnoses with genetic data to test whether the connection holds up under different kinds of evidence.

Among the participants, 3,026 had been diagnosed with ADHD. During an average follow-up of just over ten years, 6.7 percent of them developed mild cognitive impairment or dementia, compared with 3.4 percent of participants without ADHD. The data came from enrollment between May 2018 and October 2023, with electronic health records reaching back to 1985, and the average participant was 56 years old at enrollment. After adjusting for age, sex, race and ethnicity, and genetic background, the researchers found ADHD was associated with a 4.6-fold higher hazard of developing cognitive impairment, with a 95 percent confidence interval of 3.99 to 5.29. That association weakened but did not disappear after further adjustments for physical illnesses, educational attainment, and health care use, the team reports in its analysis of ADHD dementia risk.

Genetics point the same way

Genetic evidence pointed in the same direction. Participants with the highest genetic susceptibility to ADHD had a 35 percent higher risk of dementia or mild cognitive impairment than those with the lowest susceptibility, the researchers report. When the two outcomes were analyzed separately, the risk was 3.07 times higher for dementia alone and 3.83 times higher for mild cognitive impairment alone. The link also persisted when at least eight years separated the ADHD diagnosis from the first signs of cognitive decline, a design meant to rule out the possibility that early dementia symptoms were being mistaken for ADHD. Because medical records and gene-based risk each told the same story, the authors say the pattern behind ADHD dementia risk is unlikely to be a quirk of how ADHD gets diagnosed.

Among participants who did develop cognitive impairment, those with ADHD reported poorer mental health and lower quality of life, along with less satisfaction in their social relationships. They also used about 20 percent more health care services in the year after diagnosis. Earlier, smaller studies had hinted at a connection, but concerns about how ADHD was diagnosed and whether other conditions explained the pattern left the question open, the authors write. The researchers say these findings call for closer monitoring and more coordinated care for older adults with ADHD, particularly once cognitive problems appear.

Association, not proof

Senior author Tharick A. Pascoal stressed that the findings show an association, not a cause. "This doesn't prove that ADHD causes dementia," he said in a university statement. "Two different kinds of evidence are pointing in the same direction." The gene-based analysis measured a polygenic risk score for ADHD, meaning the higher risk showed up not only in people with a formal diagnosis but also in people carrying more ADHD-linked genetic variants.

In a statement released Wednesday, psychiatrist Daniel Amen, founder of Amen Clinics, called for greater attention to lifelong brain health. "For too long, ADHD has been treated primarily as a problem with attention, behavior, or motivation," he said. "But ADHD is a brain-based condition." His statement did not come from the research team, and the study did not examine his clinic's brain imaging methods. The authors say open questions remain, including whether ADHD medications or better cardiovascular health might lower the long-term risk.

The timing of the finding matters for clinics. Adults diagnosed with ADHD in childhood are now reaching middle age in larger numbers than any previous generation, and many people receive their first ADHD diagnosis as adults. Doctors who treat those patients may need new habits for watching memory and thinking skills over time, the researchers say. They also point to a need for research into whether treatment for adult ADHD changes the trajectory, and whether habits that protect the heart also protect the brain. For now, the results give clinicians one more reason to take cognitive complaints from older patients with ADHD seriously. More detail on the study design is available in the JAMA Psychiatry paper summary, and the clinic response is published alongside the release.