NEW YORK, Sept 13: Recent research suggests that getting enough sleep may help maintain brain health and reduce the risk of dementia. Insomnia, a sleep disorder characterized by difficulty falling or staying asleep, has long been linked to various health problems, including cognitive decline, dementia, and Alzheimer’s disease.

A new study reveals that people suffering from chronic insomnia are at a higher risk of developing dementia or mild cognitive impairment (MCI) compared to those with non-chronic insomnia. This condition is also associated with faster brain aging.

What is chronic insomnia?

It is estimated that over 16% of the global population experiences insomnia, where individuals struggle to fall or stay asleep. Chronic insomnia specifically refers to difficulty sleeping at least three nights a week for more than three months.

Previous research has connected insomnia not only to neurological issues such as dementia but also to health problems like type 2 diabetes, depression, obesity, high blood pressure, and heart disease.

Published recently in Neurology, the journal of the American Academy of Neurology, the study followed 2,750 cognitively healthy adults averaging 70 years old, with 16% experiencing chronic insomnia. Over an average period of 5.6 years, participants’ sleep habits were monitored alongside cognitive testing and brain scans to assess white matter hyperintensities and beta-amyloid plaques—biomarkers commonly linked to Alzheimer’s disease.

Lead researcher Dr. Diego Z. Carvalho of the Mayo Clinic explained that the study aimed to understand whether insomnia impacts brain health through Alzheimer’s-related changes, cerebrovascular effects on white matter, or both.

The results showed that individuals with chronic insomnia had a 40% higher likelihood of developing dementia or MCI than those with non-chronic insomnia. This increased risk corresponds to an equivalent of 3.5 years of additional brain aging.

Dr. Carvalho noted that the impact of insomnia on dementia risk was greater than known risks such as having two cardiometabolic conditions like hypertension and diabetes or being 3.5 years older.

“This finding highlights insomnia as a potentially modifiable risk factor that deserves greater attention, especially given how common it is among older adults,” he said.

Sleep duration and brain changes

The study also found that participants who slept fewer hours than usual showed increased white matter hyperintensities and amyloid plaque buildup in the brain, which may explain the link between insomnia and cognitive decline.

Dr. Carvalho emphasized that reduced sleep with insomnia may contribute to cognitive issues through two independent mechanisms: Alzheimer’s pathology and cerebrovascular damage.

Importance of recognizing and treating insomnia

Despite its prevalence, insomnia remains under-recognized and undertreated, especially in older adults who often view poor sleep as a normal part of aging. Dr. Carvalho stressed the need for healthcare providers to routinely assess sleep health, particularly in older populations, and not to confine insomnia management to specialized sleep clinics.

He advocates for wider implementation of cognitive behavioral therapy for insomnia (CBT-I) in primary care settings, noting that online treatment options have improved access but further efforts are needed.

Christopher Allen, MD, a sleep medicine specialist and neurologist, finds the study’s findings clinically plausible, highlighting how insomnia affects cognition, amyloid biology, and cerebrovascular health. He encourages personalized care addressing related conditions like sleep apnea and mood disorders, stating that improving sleep has major public health benefits.

Dr. Allen views chronic insomnia as more than fatigue—it’s linked to declines in attention, memory, and processing speed over time. He considers CBT-I the gold standard for treatment and believes managing insomnia should be part of brain health prevention strategies.

Dr. Allen calls for further studies with objective sleep measurements and diverse populations to explore how insomnia treatments and medications affect cognitive outcomes and brain biomarkers.

Megan Glenn, PsyD, a clinical neuropsychologist, welcomes the study for linking poor sleep to measurable brain changes and future cognitive decline risk. She stresses that addressing modifiable risk factors like sleep, blood pressure, hearing, and physical activity could prevent or delay up to 45% of dementia cases.

Dr. Glenn urges more research using objective sleep data to clarify which sleep features most affect brain health and to test whether treating insomnia alters dementia risk.