Insomnia and Dementia: The Two-Way Relationship September 17, 2025 Most of us know how exhausting it feels after a sleepless night. But when insomnia becomes persistent, its impact can reach far beyond next-day fatigue. Researchers are finding evidence that sleep problems and dementia may influence each other, creating a cycle that can affect memory, mood, and overall health.1 How Common Is Insomnia? Insomnia is widespread. Around 30% of adults globally report at least one symptom, such as trouble falling asleep, staying asleep, or waking too early.2 In Australia, up to 60% of people say they have sleep difficulties, and 10–15% meet criteria for chronic insomnia that interferes with daily life.3 The financial impact is huge — costing the Australian economy about $11 billion each year through healthcare expenses, reduced productivity, and poorer quality of life.3 What the Research Suggests Large studies suggest that insomnia may be linked with a higher chance of cognitive decline and dementia.1 A pooled analysis of more than 9 million people across many studies found insomnia was associated with a 36% greater risk of dementia overall, a 52% increased risk of Alzheimer’s disease, and more than double the risk of vascular dementia.4 Another study showed that people with difficulty falling asleep had a 51% higher risk of dementia.5 Dementia’s Effect on Sleep The relationship runs both ways. People with dementia often develop serious sleep problems, from difficulty falling asleep to waking repeatedly at night or feeling excessively sleepy during the day. Studies suggest that up to 44% of people with Alzheimer’s disease have significant sleep disturbances, and the figure can climb to 90% in Lewy body or Parkinson’s dementia.5 For those with vascular dementia, sleep problems appear 2.5 times more frequent than in other types.5 These disturbances can worsen confusion and memory loss, and they also increase caregiver stress and risk of falls. Why Sleep Matters for Brain Health Scientists are still working to fully understand why insomnia and dementia are linked, but several mechanisms are thought to be involved4,5: Amyloid build-up: Poor sleep may increase levels of amyloid-β in the brain, a key protein involved in Alzheimer’s disease. Genetic interactions: Sleep fragmentation might worsen the impact of certain genetic risk factors, such as the APOEε4 gene. Brain protection: Sleep loss may make the blood–brain barrier more “leaky,” allow inflammation to rise, and create oxidative stress, all of which can damage brain cells. Everyday function: On a practical level, poor sleep also disrupts the prefrontal cortex — the part of the brain responsible for decision-making, focus, and problem-solving — which may accelerate age-related cognitive changes. While the precise pathways are not fully clear, the evidence points to sleep as an important player in brain health. The Takeaway Not everyone with insomnia will go on to develop dementia, but the research shows enough of a link to take sleep problems seriously. Getting help early may improve daily wellbeing and could reduce longer-term risks. If you regularly struggle to fall or stay asleep, or you feel drained despite spending time in bed, speak with your doctor. Treatment is available — and improving sleep might protect not only your mood and energy, but also your memory and independence in the years to come. How Sove CPAP Clinic Can Help Founded in 2008, Sove CPAP Clinic has grown to become a leading provider of respiratory and sleep services and products in Australia, with over 60 clinics nationwide. Our comprehensive clinical team includes Respiratory & Sleep Specialists, Sleep Technologists, and CPAP Consultants, ensuring that you receive comprehensive and personalised care. All medical procedures, including sleep studies and lung function testing, are bulk billed to all Australians, with minimal wait time. If you would like to speak to a Respiratory & Sleep Physician, book a bulk-billed sleep study, or seek advice for your sleep apnea, you can reach us at 1300 76 29 39 or info@thecpapclinic.com.au. ALWAYS FOLLOW THE DIRECTIONS FOR USE. CPAP is used for Obstructive Sleep Apnea treatment. When considering whether a sleep study or CPAP is right for you, speak to your doctor. Medicare criteria and T&Cs apply. References Tian, Zi-Yue, et al. “Alzheimer’s Disease and Insomnia: A Bibliometric Study and Visualization Analysis.” Frontiers in Aging Neuroscience, vol. 17, 8 Apr. 2025, https://doi.org/10.3389/fnagi.2025.1542607. Accessed 13 May 2025. Roth, Thomas. “Insomnia: Definition, Prevalence, Etiology, and Consequences.” Journal of Clinical Sleep Medicine, vol. 3, no. 5, 14 Nov. 2019, https://doi.org/10.5664/jcsm.26929. “Insomnia - Prevalence.” sleepprimarycareresources.org.au, www.sleepprimarycareresources.org.au/insomnia/epidemiology. Meng, Mingxian, et al. “Insomnia and Risk of All-Cause Dementia: A Systematic Review and Meta-Analysis.” PLOS ONE, vol. 20, no. 4, 9 Apr. 2025, p. e0318814, https://doi.org/10.1371/journal.pone.0318814. Accessed 28 Apr. 2025. Wong, Roger, and Margaret Anne Lovier. “Sleep Disturbances and Dementia Risk in Older Adults: Findings from 10 Years of National U.S. Prospective Data.” American Journal of Preventive Medicine, vol. 64, no. 6, Jan. 2023, https://doi.org/10.1016/j.amepre.2023.01.008.
