Large Review Links Insomnia to 26% Higher Stroke Risk and More Hospital Stays

The study was published in late September 2026 in the journal Sleep Medicine Reviews. Researchers from Austria, Germany, Italy and Switzerland did not run a new experiment. They pulled together about 20 earlier review studies, which covered millions of participants across multiple countries. This approach is sometimes called an umbrella review. It asks what the whole body of research says, rather than relying on one study.

Besides the stroke finding, people with insomnia had nearly 30% higher odds of being hospitalized for any reason, according to ABC News. The review also found that people with insomnia were more likely to have depression and to have attempted suicide than people without insomnia. It also found a connection between insomnia and dementia, particularly Alzheimer's disease.

Insomnia is the most common sleep disorder in the United States, according to the National Institutes of Health. It makes it hard to fall asleep, stay asleep or get goodquality sleep.

The findings show associations only. They do not prove that insomnia causes any of these conditions. Dr. Stefan Seidel, an author of the study and a neurology professor at the Medical University of Vienna, urged calm. "An increased risk at the population level does not mean that an individual with insomnia will develop dementia, depression or have a stroke," he told ABC News.

Seidel said the results instead give "another reason to take persistent sleep problems seriously, identify possible underlying causes and provide evidence-based treatment when appropriate." Lead author Luca Vignatelli, of the IRCCS Institute of Neurological Sciences in Bologna, Italy, framed it as a signal. "Insomnia deserves attention as a warning sign of the status of brain and mental health," he said.

Sleep and mood appear to feed each other. Dr. Thanuja Hamilton, a board-certified sleep medicine physician at Advocare, told ABC News that anxiety and depression can disrupt sleep. Poor sleep, in turn, can make people more irritable, more anxious and less resilient to stress. That can make it harder to sleep again.

On dementia, the NIH says sleep plays a role in clearing waste products linked to impaired brain function and Alzheimer's disease from the brain. Hamilton described it as the brain taking out the trash, and her view is that poor or short sleep could allow more of that waste to build up. That is an explanation offered by an expert, and the new review does not show it is the cause.

The treatment news is the encouraging part. Cognitive behavioral therapy for insomnia, known as CBT, is often the first option for long-term insomnia, according to the NIH. It works on thoughts and behaviors that interfere with sleep. Techniques can include adjusting sleep schedules and limiting time spent awake in bed. Hamilton called it the gold standard. She also said it is difficult and time-consuming, "but it is worth it."

Experts also pointed to everyday habits. One of the most important, they said, is a consistent sleep schedule, because the body's internal clock likes regularity. They also advised turning off the TV or phone 30 to 60 minutes before bed and avoiding coffee or alcohol late in the day. Trying harder to sleep tends to backfire, Hamilton noted.

The review shows associations, not causes, and that is the weakest point of the argument: it cannot tell us whether insomnia drives these conditions, whether they drive insomnia, or whether something else underlies both.

The practical message is modest but useful. Vignatelli said, "Sleep should be a topic to discuss with your doctor when talking about health, at any age." If you or someone you know is having thoughts of suicide, free, confidential help is available 24 hours a day by calling or texting 988.

What to watch next

Studies that test whether treating insomnia, such as with CBT, actually lowers the risk of stroke, depression and dementia, which this review cannot answer.

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