“Insomnia May Threaten Brain Health” — Linked to a 26% Higher Risk of Stroke, as Well as Dementia and Depression
Italian researchers analyzed studies from around the world
Insomnia linked to a 26% higher risk of stroke and a 28% higher risk of hospitalization
Higher risks of dementia, depression and suicide — a potential “warning sign” for brain health
Insomnia may be linked to a range of brain and mental health problems, including dementia, stroke and depression, according to a new study. A research team led by Dr. Luca Vignatelli at the Institute of Neurological Sciences in Bologna, Italy, analyzed findings from studies conducted around the world and found significant associations between insomnia and several neurological and mental health conditions.
Insomnia is one of the most common sleep disorders among adults. An estimated 22% of the general population is thought to meet international diagnostic criteria for insomnia, making these findings potentially relevant to a large number of people.
The researchers used an umbrella systematic review, a method that brings together and analyzes findings from previously published systematic reviews and meta-analyses. This approach allows researchers to compare evidence from multiple studies and identify patterns across the existing literature. The team searched the medical databases MEDLINE and EMBASE for studies published through August 2025.
The researchers examined dementia, stroke, depression and suicide as indicators of brain and mental health, while mortality, hospitalization and occupational injuries were assessed as broader health outcomes. They included 16 previously published systematic reviews and conducted their own analyses of individual studies for outcomes such as stroke, occupational injuries and hospitalization, for which comprehensive reviews were not available.
The analysis found that people with insomnia had a 26% higher risk of stroke than those without insomnia. They also had a 28% higher risk of hospitalization from any cause.
For dementia, most of the systematic reviews examined found an association with insomnia. The link was particularly consistent for Alzheimer’s disease across several studies. The risk of depression was approximately three times higher among people with insomnia, while the risks of suicide-related outcomes—including suicide death, attempts and suicidal thoughts—were also elevated.
However, insomnia itself was not associated with an increased risk of death from any cause.
These findings are important because insomnia may involve more than simply having difficulty sleeping. Poor sleep can leave the body in a prolonged state of arousal, potentially affecting blood pressure, heart rate and stress-hormone levels. Over time, these changes may contribute to inflammation and vascular problems, which could increase the risk of conditions such as stroke.
Insomnia may also affect mental health. Persistent sleep problems can lead to daytime fatigue and difficulty concentrating, while potentially worsening negative thoughts and contributing to depression and anxiety.
However, the researchers emphasized that the findings do not prove that insomnia directly causes stroke, dementia or other conditions. The studies included in the analysis used different definitions of insomnia, and many did not adequately account for the use of sleeping medications. In studies that did consider sleep medication use, the associations with health risks were often less clear.
In other words, insomnia may be better understood as a potential marker of declining overall health rather than a direct cause of these diseases.
Dr. Vignatelli said the findings suggest that insomnia may be more than simply a problem with getting enough sleep and could serve as an important indicator of a person’s overall health. He emphasized the need to recognize and manage insomnia as part of broader health care.
Professor Stefan Seidel of the Medical University of Vienna, a co-author of the study, also stressed that sleep should be considered an important part of brain health at every age. He called for greater awareness of insomnia and its treatment, as well as the inclusion of sleep health in health-promotion programs in communities, schools and workplaces.
The study, titled “Insomnia as risk factor for brain, mental and general health consequences: an umbrella systematic review,” was accepted for publication in the international journal Sleep Medicine Reviews in September 2026.
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