Overview

• Tracking 2,750 cognitively healthy adults for about 5.6 years, the study found those with chronic insomnia had a 40% higher incidence of mild cognitive impairment or dementia, roughly equivalent to 3.5 years of additional brain aging.
• Imaging data tied reduced recent sleep to more white matter hyperintensities and amyloid plaques, suggesting pathways involving both small‑vessel disease and Alzheimer‑type pathology.
• Participants carrying the APOE ε4 gene and experiencing insomnia showed steeper declines in memory and thinking skills than noncarriers.
• Clinicians highlight insomnia as a treatable risk factor and recommend evidence‑based care such as CBT‑I and sleep‑hygiene strategies; CNN reports those who increased sleep time or used medication did not show the same cognitive detriment.
• Authors note key limitations, including reliance on medical‑record diagnoses and limited objective sleep measures, and call for randomized trials and diverse cohorts to test whether treating insomnia alters dementia risk.