Chronic Insomnia Is Bad for the Brain. Like, Really Bad

If you’re a chronic insomniac, you might experience faster declines in memory and thinking skills than your better-sleeping fellows. In other words, your brain might age faster.

In a study published Wednesday in the journal Neurology, researchers revealed that people with chronic insomnia, described as having trouble sleeping at least three days a week for three months or more, were significantly more likely to develop mild cognitive impairment or dementia than their healthy counterparts.

“Insomnia doesn’t just affect how you feel the next day—it may also impact your brain health over time,” Diego Carvalho, a Mayo Clinic neurologist and co-author of the study, said in an American Academy of Neurology statement. “We saw faster decline in thinking skills and changes in the brain that suggest chronic insomnia could be an early warning sign or even a contributor to future cognitive problems.”

3.5 years older

To clarify, the researchers don’t know if insomnia causes brain aging; they just highlight an association. In the study, the team tracked over 2,500 cognitively healthy people with an average age of 70 for an average of 5.6 years. 16% of the participants had chronic insomnia.

14% of the people with chronic insomnia developed mild cognitive impairment or dementia during the study, while only 10% of participants without insomnia developed those same symptoms. After the researchers took into account differences such as high blood pressure, use of sleep medications, age, and a diagnosis of sleep apnea, they revealed that insomniac participants had a 40% greater risk of developing mild cognitive impairment or dementia than those without insomnia. That’s equivalent to 3.5 extra years of aging. Their performances in thinking tests also decreased faster.

Of the patients with insomnia, those who reported less sleep than usual in the past two weeks were more likely to get lower cognitive test scores at the beginning of the study, equivalent to being four years older. Furthermore, they had more white matter hyperintensities (potentially damaged brain tissue from small vessel disease) and amyloid plaques (a protein associated with Alzheimer’s disease). The buildup of the latter was akin to that in people with a known genetic risk factor.

Maintaining brain resilience

“Our results suggest that insomnia may affect the brain in different ways, involving not only amyloid plaques, but also small vessels supplying blood to the brain,” Carvalho said. “This reinforces the importance of treating chronic insomnia—not just to improve sleep quality but potentially to protect brain health as we age. Our results also add to a growing body of evidence that sleep isn’t just about rest—it’s also about brain resilience.”

Participants who claimed to get more sleep than usual in the past two weeks had greater chances of having fewer white matter hyperintensities at the start of the study.

The researchers admit that their results are limited by the fact that the insomnia diagnoses were from medical records that don’t indicate the severity of the symptoms or include undiagnosed cases. Nonetheless, the point of the study seems clear enough to me—get enough sleep. And if you can’t, get help.