I’ve spent much of my career studying cognitive decline. Before I specialized in Lyme disease, I taught medical students about dementia. I ran programs evaluating memory loss in older adults. So when I say that Lyme disease and dementia can be confused, I don’t say it lightly.
One of my patients was referred to me with a working diagnosis of dementia. He had memory issues, word-finding problems, trouble concentrating. But the timeline didn’t quite add up. He wasn’t deteriorating in the typical way. He had a history of outdoor exposure — and no one had considered Lyme.
He was diagnosed and treated for Lyme disease.
How Lyme Disease Can Mimic Dementia
The overlap between Lyme disease and dementia is more common than many realize. Lyme disease can cause:
- Brain fog
- Short-term memory loss
- Difficulty concentrating
- Word retrieval problems
- Mood changes or irritability
- Slowed processing speed
These symptoms can resemble early Alzheimer’s or mild cognitive impairment (MCI). But unlike progressive neurodegenerative diseases, Lyme disease-related cognitive decline can be reversible with treatment. When Lyme disease is the underlying infection and is treated, dementia-like symptoms can resolve.
Lyme Disease and Dementia: Know the Difference
Key signs that cognitive issues may be Lyme-related rather than neurodegenerative:
- Sudden or fluctuating symptoms
- Coexisting fatigue, pain, or neuropathy
- A history of outdoor exposure, even years ago
- Mood instability or neurologic symptoms
- Negative dementia screening tests but persistent complaints
A missed diagnosis can delay treatment — and allow the infection to progress.
A Famous Example: Kris Kristofferson
The country music legend Kris Kristofferson was misdiagnosed with Alzheimer’s. His memory issues and confusion were attributed to aging. But the underlying cause was Lyme disease. After being properly diagnosed and treated, his mental clarity returned.
CBS News: Kris Kristofferson’s Lyme disease misdiagnosed as Alzheimer’s
Lyme Brain Fog vs. Alzheimer’s: Why It Matters
Not every case of brain fog is Alzheimer’s. Not every older adult with memory problems has dementia.
If clinicians don’t ask about tick exposure, if they don’t consider Lyme disease, they risk missing a treatable cause of cognitive decline. It’s not just a misdiagnosis — it’s a lost opportunity to help someone recover.
What Doctors Should Do
- Include Lyme disease in the differential diagnosis for patients with new cognitive symptoms
- Ask about tick exposure, outdoor activities, or prior rashes — even years ago
- Recognize that Lyme tests can miss cases; consider clinical judgment
- Reassess cognitive status after antibiotic treatment in suspected cases
Can Lyme Disease Cause Lewy Body Dementia?
The question of whether Lyme disease could directly cause dementia was addressed by Wormser and colleagues in their review of a case involving a 69-year-old woman who died 15 years after her initial Lyme disease infection with a clinical diagnosis of Lewy body dementia.
The woman had initially presented with an erythema migrans rash, headache, joint pain, and fever. Her symptoms resolved with 10 days of doxycycline. Over time, she developed a sleep behavior disorder, cognitive problems including processing speed, mental tracking, and word-finding difficulties, as well as photophobia and myoclonic jerks.
An autopsy revealed the presence of Borrelia burgdorferi in the brain and spinal cord tissue.
However, the authors concluded that no convincing evidence exists that Lyme disease is a cause of either Alzheimer disease or Lewy body dementia. They noted that dementia-like syndromes from Lyme disease occur as a consequence of chronic progressing meningoencephalomyelitis — a very rare late neurologic manifestation.
Importantly, Wormser et al. acknowledged that anecdotal evidence does suggest that Lyme disease may rarely cause dementia, and that cognitive complaints such as concentration or memory disturbances are common in patients with Lyme disease.
Watch Dr. Cameron discuss this case:
Don’t Dismiss Reversible Cognitive Decline
As someone trained in both geriatrics and Lyme disease, I’ve seen firsthand that brain fog from Lyme disease is documented, measurable, and often treatable.
When we reframe cognitive decline as a medical puzzle, not a foregone conclusion, we give patients something essential: hope.
Ruling Out Other Conditions
As a Lyme disease specialist, I’ve seen how symptoms like fatigue, brain fog, and pain can overlap with other conditions. That’s why I encourage patients to work closely with their primary care doctor — and, if needed, with specialists — as part of their Lyme disease evaluation. A broad, thoughtful evaluation helps ensure nothing important is missed and allows for a more focused, effective treatment plan.
Frequently Asked Questions
Can Lyme disease be mistaken for dementia?
Yes. Lyme disease and dementia share symptoms including memory loss, confusion, slowed thinking, and word-finding problems. Unlike neurodegenerative dementia, Lyme-related cognitive decline can improve with treatment.
Can Lyme disease cause Alzheimer’s?
Current evidence does not support Lyme disease as a direct cause of Alzheimer’s. However, Lyme disease can produce cognitive symptoms that closely mimic Alzheimer’s and may be misdiagnosed as such.
How do you tell the difference between Lyme brain fog and dementia?
Lyme-related cognitive symptoms tend to fluctuate, appear alongside fatigue and pain, and may follow tick exposure. Neurodegenerative dementia typically progresses steadily over time.
Is Lyme-related cognitive decline reversible?
In many cases, yes. When Lyme disease is identified and treated, cognitive function can improve significantly — unlike progressive neurodegenerative conditions.
Should older adults with memory problems be tested for Lyme disease?
Yes, particularly if they live in or have visited tick-endemic areas, have a history of outdoor exposure, or present with cognitive symptoms alongside fatigue, pain, or neurologic complaints.
References
- Wormser GP, Marques A, Pavia CS, et al. Lack of Convincing Evidence that Borrelia burgdorferi Infection Causes Either Alzheimer’s Disease or Lewy Body Dementia. Clin Infect Dis. 2021.
- Gadila SKG, Rosoklija G, Dwork AJ, Fallon BA, Embers ME. Detecting Borrelia Spirochetes: A Case Study With Validation Among Autopsy Specimens. Front Neurol. 2021;12:628045.
- Haider A, Spurling BC, Sanchez-Manso JC. Lewy Body Dementia. StatPearls. 2022.
