Can younger people’s mental health signal dementia risk?

Mental disorders were more strongly associated with dementia than chronic physical diseases—an outcome the researchers did not expect. (Credit: Getty Images)

Preventing mental disorders in young people might reduce or delay the burden of dementia in older people, according to a new study.

Investing in good mental health care for young people—including evidence-based interventions for mental health problems—could help reduce the burden of neurodegenerative disease, researchers say.

The study of 1.7 million New Zealanders—aged 21 to 60 years at baseline—followed across three decades (1988 to 2018) tested whether people with mental disorders are at increased risk for subsequent dementia.

Much research and treatment in geriatrics focuses on physical diseases and ignores mental health, says Leah Richmond-Rakerd, assistant professor in the University of Michigan’s psychology department and the study’s lead author.

Richmond-Rakerd and colleagues chose New Zealand for its capacity to link medical records and other administrative databases at the population level—something not possible in the United States.

The long-term, follow-up use of hospital records, and the ability to establish that mental disorders preceded dementia set this study apart from others.

Among the study’s findings:

  • Mental disorders were more strongly associated with dementia than chronic physical diseases—an outcome the researchers did not expect.
  • Preexisting chronic physical illness or socioeconomic deprivation did not explain the association between mental disorders and dementia.
  • The connection between mental health problems and dementia was seen for both men and women, for both early-onset and later-onset dementias, for different types of mental health conditions, and for both Alzheimer’s and non-Alzheimer’s dementias.

Richmond-Rakerd says mental disorders are salient early-warning signs for subsequent dementia. People with mental disorders could be encouraged to engage in health behaviors to reduce dementia risk—for instance, to increase their physical activity, which so far is one promising way to potentially help prevent dementia, the researchers say.

The mechanism for the association is not clear, but could involve several factors, says coauthor Avshalom Caspi, professor of psychology and neuroscience at Duke University.

For instance, a lifelong brain vulnerability may manifest itself as mental health problems earlier in life and dementia later in life. Or medication for mental disorders (such as antipsychotics) might increase the risk for dementia, he says.

The researchers caution that most people with mental-health problems will not develop dementia.

“Mental health problems are not a ‘life sentence’ that always results in dementia,” Richmond-Rakerd says.

The study appears in JAMA Psychiatry. Additional coauthors are from the University of Auckland and Duke University.

Support for the research came from the National Institute on Aging, the UK Medical Research Council, the National Institute of Child Health and Development through the Duke Population Research Center, and the NIA through the Center for Advancing Sociodemographic and Economic Study of Alzheimer’s Disease and Related Dementias.

Source: University of Michigan