The correct spelling is "Parkinson's"

Parkinson's is spelled P-A-R-K-I-N-S-O-N-'-S, with a capital P and an apostrophe before the final S. The apostrophe is there because the condition is named after James Parkinson, the English doctor who first described it in 1817. The possessive form — showing that it belongs to or comes from his name — is why you see the apostrophe.

In medical writing and on official documents, you may also see it written as "Parkinson disease" without the apostrophe or the final S. Both forms are correct. The version with the apostrophe (Parkinson's) is more common in everyday conversation and patient materials. The version without (Parkinson disease) appears more often in medical journals and formal clinical settings.

When you are filling out forms, writing to your doctor, or searching for information online, either spelling will be understood. Most search engines and medical websites recognize both versions and will direct you to the same resources.

Key Takeaways

  • The standard spelling is "Parkinson's" with a capital P and an apostrophe before the final S.
  • "Parkinson disease" without the apostrophe is also correct and is the preferred form in medical journals.
  • The apostrophe exists because the condition is named after Dr. James Parkinson, who described it in the early 1800s.
  • Both spellings are recognized by search engines, medical websites, and healthcare providers.

Why the apostrophe matters in medical names

Medical conditions named after people who discovered them follow a possessive naming pattern. This is why you see apostrophes in conditions like Alzheimer's disease, Crohn's disease, and Down syndrome (though Down syndrome is named after a person and uses a different convention). The apostrophe signals that the condition is associated with or named for that person.

Over time, medical style guides have moved toward dropping the apostrophe in formal writing. The American Medical Association and many medical journals now prefer "Parkinson disease" without the possessive form. This shift happened partly to simplify medical terminology and partly because modern doctors do not think of the condition as "belonging to" the person who named it — it is simply what we call the condition now.

In patient education materials, hospital websites, and conversations with your doctor, you will see both versions used interchangeably. There is no penalty for using either one.

Common misspellings to avoid

The most frequent mistakes are spelling it as "Parkinsons" (missing the apostrophe), "Parkinsons disease" (missing the apostrophe but adding the word disease), or "Parkinson's disease" with an extra word. None of these are wrong in the sense that people will not understand you, but they are not the standard spelling.

Less common but still seen: "Parkinsons Syndrome" or "Parkinson Syndrome." Parkinson's is not a syndrome — it is a disease or disorder. Using the word syndrome changes the meaning slightly and may confuse search results or medical records.

If you are unsure which version to use in a specific context — such as on a medical form or in a formal letter — the safest choice is "Parkinson's disease" with the apostrophe and the word disease. This version appears on most official health websites and in patient guides.

How spelling appears in different places

Medical journals and research papers typically use "Parkinson disease" without the apostrophe. If you are reading a scientific study or a detailed clinical article, this is the version you will encounter most often.

Patient guides, hospital websites, and educational materials from organizations like the Parkinson's Foundation usually use "Parkinson's" with the apostrophe. This is the version you will see in most places where you are learning about the condition as a patient or caregiver.

Insurance documents, prescription records, and medical billing systems may use either version. The important thing is that your condition is recorded consistently in your own medical records so that your doctors can find your history easily.

What to do if you see it spelled differently

If a website, document, or medical record spells it differently than you expect, do not worry. As long as the spelling is close enough to be recognizable — "Parkinson's," "Parkinsons," or "Parkinson disease" — the meaning is clear to healthcare providers and search engines.

If you are filling out a form and there is a blank space for the condition name, either "Parkinson's" or "Parkinson disease" will be accepted and understood. If you are concerned about consistency in your medical records, you can ask your doctor's office which spelling they use in their system.

Frequently Asked Questions

Is it ever correct to spell it "Parkinsons" without the apostrophe?

Technically, no — the standard spelling includes either an apostrophe (Parkinson's) or the full phrase "Parkinson disease." However, many people write it without the apostrophe in casual contexts, and it will still be understood. For official documents or medical records, use one of the two standard forms.

Should I write "Parkinson's disease" or just "Parkinson's"?

Both are correct. "Parkinson's disease" is more formal and appears in medical documents. "Parkinson's" alone is shorter and is fine for everyday use, emails, and conversations. Choose whichever feels natural for the context.

Do I need to capitalize the P?

Yes. Because it is named after a person (James Parkinson), it is a proper noun and always starts with a capital P, whether you write "Parkinson's" or "Parkinson disease."

What if my doctor's office spells it differently than I do?

That is normal. Different offices and different systems may use different versions. As long as the spelling is recognizable, your medical records will be linked correctly. If you want consistency, you can ask which version they prefer, but it is not necessary.

Is "Parkinson Syndrome" an acceptable spelling?

No. Parkinson's is a disease, not a syndrome. Using the word syndrome changes the medical meaning. Stick with "Parkinson's disease" or "Parkinson disease" to be accurate.