In a discovery that connects the dots between sleep quality and brain health, researchers at Washington University in St. Louis have found that a widely-prescribed insomnia medication may have unexpected benefits for brain proteins linked to Alzheimer’s disease.
The Remarkable Discovery
The study, published in the Annals of Neurology, revealed something both surprising and promising: participants who took suvorexant—a medication commonly prescribed for insomnia—experienced a 10-20% reduction in amyloid-beta proteins circulating in their cerebrospinal fluid after just two nights of use.
These amyloid-beta proteins are the same ones that form the characteristic plaques clogging brain tissue in Alzheimer’s disease patients. What’s more, higher doses of the medication temporarily reduced levels of hyperphosphorylated tau—another protein linked to Alzheimer’s progression and neuronal death.
“If you can reduce tau phosphorylation, potentially there would be less tangle formation and less neuronal death,” explained Dr. Brendan Lucey, director of Washington University’s Sleep Medicine Center, who led the research.
How They Made This Discovery
The Washington University team took an unusually direct measurement approach in their study. They recruited 38 middle-aged participants (45-65 years old) who showed no signs of cognitive impairment or sleep problems—an important factor since they wanted to study the medication’s effects in healthy brains.
Researchers placed catheters to collect cerebrospinal fluid samples every two hours for 36 hours straight—through nighttime sleep, the following day, and another night. Participants randomly received either a clinical dose of suvorexant, a higher dose, or a placebo pill.
This continuous sampling allowed researchers to track protein level changes in real-time as the medication took effect. The results showed clear differences between the groups receiving the medication and those receiving placebo.
The Unexpected Mechanism
Here’s where things got particularly interesting: despite the medication not significantly improving objective sleep quality measures between the groups, the protein levels still changed.
This suggests the medication might work through mechanisms beyond simply improving sleep—potentially acting directly on protein production or clearance pathways in the brain. Even more curious, researchers observed the most significant drop in amyloid-beta with the standard clinical dose of suvorexant rather than the higher experimental dose.
Why Sleep Matters for Brain Health
To understand why this finding is significant, we need to look at what happens in our brains during sleep.
During deep sleep phases, your brain undergoes something akin to a nightly cleaning service. Brain cells actually shrink slightly during sleep, creating wider channels for cerebrospinal fluid to flow through and flush away accumulated proteins and other waste products from the day’s neural activity.
This natural cleaning mechanism—sometimes called the glymphatic system—works most efficiently during deep, slow-wave sleep. When sleep is disrupted or insufficient, this crucial cleanup process may be compromised.
Previous research has shown that even one night of poor sleep can cause amyloid-beta levels to spike. This suggests that chronic sleep issues might allow these proteins to accumulate faster than the brain can clear them.
Important Cautions and Limitations
Despite the promising results, Dr. Lucey explicitly warns that “it would be premature for people who are worried about developing Alzheimer’s to interpret it as a reason to start taking suvorexant every night.”
Several important limitations need consideration:
- This was an extremely short study—just two nights—with a small sample of healthy individuals.
- The effect on tau protein was particularly fleeting. While levels dropped initially, they rebounded within 24 hours of taking the medication, suggesting any protection might be very temporary.
- The benefits observed in healthy middle-aged adults might not translate to older individuals already experiencing cognitive decline or those with diagnosed sleep disorders.
- Long-term sleeping pill use carries significant risks, including physical and psychological dependence, rebound insomnia when stopping the medication, potentially suppressing crucial deep sleep phases, side effects including daytime drowsiness, and increased fall risk, especially in older adults.
The Broader Context of Alzheimer’s Research
This study comes at a time when researchers are rethinking how Alzheimer’s disease develops. The leading theory—that abnormal protein clumps drive Alzheimer’s pathology—has come under intense scrutiny lately after decades of research aimed at lowering amyloid levels has not translated into effective treatments that prevent or slow the disease.
This has prompted scientists to consider whether protein accumulation might be a symptom rather than a cause of the underlying disease processes. If that’s the case, treatments focused solely on reducing these proteins might miss the actual disease mechanisms.
What This Means for Future Research
The Washington University team hopes to conduct longer studies examining whether sustained use of sleep medications produces lasting effects on protein levels in populations at higher risk for Alzheimer’s. They’re also exploring how these medications might interact with other emerging Alzheimer’s prevention strategies.
“I’m hopeful that we will eventually develop drugs that take advantage of the link between sleep and Alzheimer’s to prevent cognitive decline,” said Dr. Lucey. But he admitted, “We’re not quite there yet.”
What You Can Do
While the research continues, sleep specialists emphasize that improving sleep through natural means remains one of the best approaches to supporting brain health:
- Maintain consistent sleep schedules
- Create a proper sleep environment
- Limit screen exposure before bed
- Exercise regularly
- Manage stress through techniques like meditation
For those struggling with persistent sleep issues, consulting a sleep specialist should take priority over self-medicating with over-the-counter sleep aids, which often provide limited benefit and can create dependence.
As the connection between sleep and brain health becomes clearer, one thing is certain: quality sleep isn’t just about feeling refreshed tomorrow—it might be crucial for cognitive health decades later.
