• Posted September 25, 2025

Lights Are Dimming For America's Brain Power, Study Says

A growing number of Americans appear to be losing their brain power, particularly younger adults, a new study says.

The U.S. has experienced a sharp increase in adults experiencing serious problems with memory, concentration and decision-making, researchers reported Sept. 24 in the journal Neurology.

Rates nearly doubled among 18- to 39-year-olds, according to the study, and the biggest increases were found among people who had less education and earned lower wages.

“Challenges with memory and thinking have emerged as a leading health issue reported by U.S. adults,” said senior researcher Dr. Adam de Havenon, an associate professor of neurology at Yale School of Medicine in New Haven, Conn.

“Our study shows that these difficulties may be becoming more widespread, especially among younger adults, and that social and structural factors likely play a key role,” he added in a news release.

For the new study, researchers analyzed survey data collected annually between 2013 and 2023 by the U.S. Centers for Disease Control and Prevention (CDC). All told, the team reviewed more than 4.5 million survey responses.

Survey participants were asked, “Because of a physical, mental or emotional condition, do you have serious difficulty concentrating, remembering or making decisions?” Those who responded “yes” were classified as having a cognitive disability.

To provide a fairer estimate, researchers excluded responses from people who reported depression, and threw out data from 2020 due to the impact of the COVID-19 pandemic on America’s psyche.

Overall, the rate of people reporting thinking problems increased from 5.3% in 2013 to 7.4% in 2023, the survey found.

For adults under 40, the rate rose sharply from 5.1% to 9.7%, nearly doubling, researchers said.

On the other hand, rates among seniors 70 and older declined slightly, from 7.3% to 6.6%.

Americans with household incomes below $35,000 consistently reported the highest rates, rising from 8.8% to 12.6% during the study period, researchers said.

Those with incomes over $75,000 had substantially lower rates but they still more than doubled, rising from 1.8% to 3.9%.

Education also appeared to help protect brain power. Adults without a high school diploma experienced an increase from 11.1% to 14.3%, compared to an increase from 2.1% to 3.6% among college graduates, the study found.

The rate of cognitive disability rose across all racial and ethnic groups studied:

• American Indian/Alaskan Native, from 7.5% to 11.2%

• Hispanic, from 6.8% to 9.9%

• Black, from 7.3% to 8.2%

• White, from 4.5% to 6.3%

• Asian, from 3.9% to 4.8%

“These findings suggest we’re seeing the steepest increases in memory and thinking problems among people who already face structural disadvantages,” de Havenon said. “We need to better understand and address the underlying social and economic factors that may be driving this trend.”

More research is needed to understand what is driving these trends, particularly among younger adults, he said.

“It could reflect actual changes in brain health, better awareness and willingness to report problems, or other health and social factors,” de Havenon said. “But regardless of possible causes, the rise is real — and it’s especially pronounced in people under 40.”

More information

Rutgers University has more on cognitive skills.

SOURCE: American Academy of Neurology, news release, Sept. 24, 2025