Believing that older people are useless or weak can actually change your brain in ways that make you more vulnerable to dementia.

Negative thinking can cause your brain to change in ways that increase your risk of getting Alzheimer’s disease.

That’s the conclusion from a new study led by the Yale School of Public Health. At the same time, researchers note that more positive perceptions of aging could also thwart the advance of the brain-destroying disease.

The negative beliefs typically include thinking that aging makes you decrepit or useless as well as other stereotypes about older people in general.

The study is the first of its kind to link brain changes in Alzheimer’s disease to a cultural-based psychosocial risk factor.

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It’s a kind of biological self-fulfilling prophecy, said Becca Levy, Ph.D., an associate professor of public health and psychology at the Yale School of Public Health. Anxiety about getting older can be internalized. That stress can, in turn, cause brain changes.

“Although the findings are concerning, it is encouraging to realize that these negative beliefs about aging can be mitigated and positive beliefs about aging can be reinforced, so that the adverse impact is not inevitable,” Levy said in a statement.

Our socialization about youth and age starts very young.

“We know from other research that children as young as 4 take in the age stereotypes of their culture and then these age stereotypes are reinforced over time,” Levy told Healthline.

The research found that it amounts to culture-based environmental risk factor for Alzheimer’s.

“This seems important because everybody is exposed to the age stereotypes of their culture and we recently found that positive age stereotypes can be bolstered and negative age stereotypes can be reduced,” she said. “This suggests that age stereotypes could be a modifiable risk factor related to Alzheimer’s disease.”

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Levy’s team is part of the Baltimore Longitudinal Study of Aging, the longest-running scientific study on aging in the United States.

Using MRIs to look at the brains of healthy people, they found that those who had more negative beliefs on aging had smaller hippocampi. The hippocampus is a section of the brain vital to memory; a smaller one is a hallmark of Alzheimer’s disease.

When study participants died, scientists examined their brains for amyloid plaques and neurofibrillary tangles, the clumps and strands of proteins that are calling cards for Alzheimer’s.

They found that people who had more negative beliefs on aging in life had a significantly greater number of plaques and tangles in their brains.

In both stages of the study, the researchers controlled for other Alzheimer’s disease risk factors, including general health, age, and a more general tendency to think negatively.

“We found that negative age stereotypes predicted the Alzheimer’s biomarkers above and beyond these factors,” Levy said.

Levy said the researchers hope people try to find ways to promote positive age stereotypes and reduce negative stereotypes associated with aging in media.

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