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.
His cognitive symptoms resolved.
He’s back to working part-time and enjoying life.

How Lyme Disease Can Mimic Dementia

The overlap between Lyme disease and dementia is more common than many realize. Lyme disease can cause:

1. 1. Brain fog

   2. Short-term memory loss

   3. Difficulty concentrating

   4. Word retrieval problems

   5. Mood changes or irritability

   6. 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. That is – when Lyme disease is the underlying infection and is treated, dementia symptoms can go away.

Lyme Disease and Dementia: Know the Difference

Key Signs of Lyme-Related Cognitive Issues:

1. 1. Sudden or fluctuating symptoms

   2. Coexisting fatigue, pain, or neuropathy

   3. A history of outdoor exposure, even years ago

   4. Mood instability or neurologic symptoms

   5. 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 real culprit was Lyme disease. After being properly diagnosed and treated, his mental clarity returned.

CBS News Report: 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 we don’t ask about tick exposure, if we don’t consider Lyme disease, we 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

1. 1. Include Lyme disease and dementia in the differential diagnosis for patients with new cognitive symptoms.

   2. Ask about tick exposure, outdoor activities, or prior rashes—even years ago.

   3. Recognize that Lyme tests can miss cases; consider clinical judgment.

   4. Reassess cognitive status after antibiotic treatment in suspected cases.

Final Thoughts: Don’t Dismiss Reversible Dementia

As someone trained in both geriatrics and Lyme disease, I’ve seen firsthand that brain fog from Lyme is real—and it’s often treatable.

When we reframe cognitive decline as a medical puzzle, not a foregone conclusion, we give patients something priceless:
Hope.

References

1. 1. Reversible causes of Dementia and Normal Pressure Hydrocephalus
   2. Lyme diseases or dementia

Ruling Out Other Conditions Matters in a Lyme Disease Evaluation

As a Lyme disease expert, 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.

This blog is for educational purposes only and is not a substitute for medical advice, diagnosis, or treatment. Please consult your healthcare provider for guidance specific to your situation.