According to a study published in the journal Neurology, chronic insomnia may lead to a faster decline in memory and thinking skills as people get older, as well as visible changes in the brain.
The study found that individuals with insomnia (defined as difficulty falling asleep, frequent awakenings, or waking up too early for at least three nights a week for three or more months) had a 40% higher risk of developing mild cognitive impairment or dementia.
While the research does not prove that insomnia directly causes cognitive decline, it does highlight a strong association between the two.
The study involved 2,750 cognitively healthy older adults, with an average age of 70, and lasted for 5.6 years. Sixteen percent of the participants had chronic insomnia. They underwent annual tests for memory and thinking skills, and some also had brain scans to check for white matter hyperintensities (markers of small vessel disease) and amyloid plaque—a protein linked to Alzheimer’s disease.
Over the course of the study, 14% of people with chronic insomnia developed mild cognitive impairment or dementia, compared to 10% of those without insomnia. The increased risk remained significant even after accounting for factors like age, blood pressure, sleep apnea, and the use of sleeping medications.
The researchers also found differences based on sleep duration. Participants who typically slept less had lower cognitive test scores at the start of the study, equivalent to someone four years older. Their brains showed more white matter hyperintensities and amyloid plaque. In contrast, those who got enough sleep had a tendency to have fewer white matter hyperintensities.
The findings suggest that insomnia may impact the brain in several ways, including the formation of amyloid plaque and affecting the small blood vessels that nourish brain tissue. This discovery further emphasizes the importance of treating chronic insomnia, not only to improve sleep quality but also to protect brain health.
