A drug borrowed from Alzheimer's treatment may finally have an answer for a forgotten disease.
For decades, dementia with Lewy bodies has lived in the shadow of Alzheimer's, treated with borrowed medicines and uncertain hope. A Swedish study tracking over a thousand patients across ten years now offers something rarer than a cure — a direction. The evidence suggests that cholinesterase inhibitors, long used for Alzheimer's, may meaningfully slow the cognitive decline of a disease that has resisted understanding, pointing medicine toward a more deliberate path for those who carry this diagnosis.
- Dementia with Lewy bodies strikes faster and harder than Alzheimer's, yet has no approved treatments of its own — leaving patients and doctors navigating largely in the dark.
- A decade-long Swedish study of 1,095 patients found that cholinesterase inhibitors like donepezil and galantamine produced significantly slower cognitive decline compared to memantine or no treatment at all.
- Patients on these inhibitors also showed a reduced risk of death in the first year after diagnosis, though that protective effect did not hold beyond that early window.
- The study is observational rather than a controlled trial, meaning it cannot confirm cause and effect — but its scale and duration make the signal difficult to dismiss.
- Researchers are now calling for updated treatment guidelines and deeper investigation into why these drugs appear to help, offering a clearer foothold in a disease long defined by uncertainty.
Dementia with Lewy bodies has long been the overlooked sibling of Alzheimer's — less studied, less understood, and treated largely by borrowing from another disease's playbook. A new Swedish study suggests that borrowed approach may have been quietly working all along.
Researchers at the Karolinska Institutet followed 1,095 people with Lewy body dementia over ten years, comparing those who received cholinesterase inhibitors — drugs like donepezil and galantamine — against those given memantine or no medication. The results were striking: patients on cholinesterase inhibitors declined significantly more slowly than the other groups, and faced a reduced risk of death in the first year after diagnosis, though that survival benefit faded over time.
The disease itself is formidable. Accounting for roughly one in ten dementia cases, it progresses more aggressively than Alzheimer's, disrupting sleep, movement, behavior, and cognition simultaneously. Cholinesterase inhibitors work by preserving acetylcholine, a brain chemical that dementia steadily depletes. Their benefit in Alzheimer's has guided treatment for years; in Lewy body dementia, the evidence has until now been fragmented and inconclusive.
Because this was an observational study rather than a clinical trial, it cannot establish cause and effect with certainty. Still, neurobiologist Maria Eriksdotter described the findings as significant enough to reshape clinical practice, calling for updated treatment guidelines. No drug is currently approved specifically for Lewy body dementia — physicians prescribe Alzheimer's medications off-label, hoping for relief. This study suggests at least one of those drug classes deserves a more deliberate and prominent role in care.
Dementia with Lewy bodies has long been the forgotten cousin of Alzheimer's disease—less studied, less understood, and until now, treated largely by guesswork. Doctors have borrowed medications from the Alzheimer's playbook, hoping something would stick. A new study from Sweden suggests they may have been onto something all along.
Researchers at the Karolinska Institutet tracked 1,095 people diagnosed with dementia with Lewy bodies over a decade, comparing those who received cholinesterase inhibitors—a class of Alzheimer's drugs—against those given memantine, another Alzheimer's medication, or no drug treatment at all. The results were striking. Patients taking cholinesterase inhibitors, particularly the drugs donepezil and galantamine, experienced significantly slower cognitive decline than the other groups. There was also a reduced risk of death in the first year after diagnosis for those on the inhibitors, though this protective effect did not persist beyond that initial period.
Dementia with Lewy bodies accounts for roughly one in every ten dementia cases, making it the second most common form after Alzheimer's. Yet it remains poorly understood. The condition is related to both Alzheimer's and Parkinson's disease, but it progresses differently and more aggressively, attacking sleep, behavior, movement, and bodily functions alongside cognition. Patients typically decline faster than those with Alzheimer's alone, making any effective treatment a significant development.
Cholinesterase inhibitors work by preserving acetylcholine, a chemical messenger in the brain that neurons produce and use to process information. As dementia takes hold, acetylcholine levels drop. These drugs slow that loss. For Alzheimer's patients, the benefit has been clear enough to guide treatment decisions for years. For Lewy body dementia, the evidence has been murkier—a patchwork of inconsistent trial results and limited long-term data that left neurologists uncertain whether the drugs actually helped.
This observational study, which followed existing medical records rather than conducting a controlled clinical trial, cannot prove cause and effect. But it does suggest the effect is real enough to warrant serious investigation. The researchers found that cholinesterase inhibitors outperformed memantine in slowing decline, though neither drug class reduced the risk of major heart events—a finding that surprised the team, since cholinesterase inhibitors have shown cardiovascular benefits in Alzheimer's patients.
Maria Eriksdotter, a neurobiologist on the research team, called the findings significant enough to reshape how doctors approach the disease. "Our results highlight the potential benefits of cholinesterase inhibitors for patients with dementia with Lewy bodies and support updating treatment guidelines," she said. Currently, no medications are approved specifically for Lewy body dementia. Doctors prescribe Alzheimer's drugs off-label, hoping for symptom relief. This study suggests at least one class of those drugs deserves a more prominent place in the treatment toolkit.
The work was published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association. Researchers acknowledge that further studies are needed to understand exactly how and why cholinesterase inhibitors help some Lewy body patients. But for a disease that has long operated in Alzheimer's shadow, the finding represents a step toward better care and, potentially, updated clinical guidelines that reflect what the data now shows.
Notable Quotes
Our results highlight the potential benefits of cholinesterase inhibitors for patients with dementia with Lewy bodies and support updating treatment guidelines.— Maria Eriksdotter, neurobiologist, Karolinska Institutet
There are currently no approved treatments for dementia with Lewy bodies, so doctors often use drugs for Alzheimer's disease for symptom relief. However, the effectiveness of these treatments remains uncertain due to inconsistent trial results and limited long-term data.— Hong Xu, neurobiologist, Karolinska Institutet
The Hearth Conversation Another angle on the story
Why does it matter that this is an observational study rather than a randomized trial?
Because we can see the pattern—people on these drugs declined more slowly—but we can't be certain the drug caused the improvement. Maybe the people who took the medication were healthier to begin with, or had better access to other care. A trial would randomize people, so you'd know the drug itself made the difference.
But you're saying the finding is still worth something?
Absolutely. It's a signal. Over ten years, across more than a thousand patients, the pattern held. That's not nothing. It tells researchers where to focus next.
What's the human reality here? Someone gets diagnosed with Lewy body dementia today—what changes for them?
Probably nothing immediately. Doctors are already using these drugs off-label. But this study gives them more confidence they're not just guessing. And it might eventually lead to official guidelines that make the drugs easier to access and prescribe.
Why is Lewy body dementia so much less known than Alzheimer's?
It's rarer, affects fewer people, and it's harder to study because it's so variable. Every patient is different. Alzheimer's has had decades of research and funding. Lewy bodies got the leftovers.
So this is partly about visibility?
Partly. But it's also about mechanism. We still don't fully understand why preserving acetylcholine helps Lewy body brains the way it helps Alzheimer's brains. That's the next question.