Nearly one in five people sent to top clinics with an “MS” label turned out not to have the disease—and Christina Applegate’s reversal put that risk in bold print.
At a Glance
- A 2019 study of specialty referrals found almost 20% were misdiagnosed with multiple sclerosis
- Misdiagnosis can expose patients to risky drugs and delay real treatment
- Experts warn the true misdiagnosis rate for all patients is likely lower than 20%
- Applegate’s public case shows the human cost—and the diagnostic fog—of MS decisions
What the new spotlight got right—and wrong
Christina Applegate says doctors told her she does not have multiple sclerosis after years of living with that diagnosis. Reporters quoted a multiple sclerosis specialist who said almost 1 in 5 people told they have the disease “didn’t actually have it,” echoing a peer-reviewed study in referrals to two academic centers. That study measured a high share of diagnostic mistakes in people already flagged as complex. It did not claim that 20% of all multiple sclerosis diagnoses are wrong.
Other experts put the broad misdiagnosis rate lower. A neurologist who studies multiple sclerosis said the best studies suggest about 10%. A 2024 review that pooled six studies estimated 15% and showed a wide range from 5% to 41%, which depends on who gets counted and where they were seen. This gap is the denominator problem: referral clinics see harder cases. Community clinics see a wider mix. Numbers shift with each group.
Why multiple sclerosis invites error
Multiple sclerosis has no single yes-or-no test. Doctors assemble clues from symptoms, magnetic resonance imaging, spinal fluid, and time. White spots on a brain scan can come from migraine, aging, or other issues. If a doctor leans too hard on a scan or misapplies criteria, the label can stick. Review articles point to overreliance on imaging and loose use of diagnostic rules as repeat offenders in false positives. The push to diagnose earlier also raises the odds of calling it wrong.
Applegate’s reversal underscores that point. Reports say her doctors concluded she did not have multiple sclerosis but did not offer a new cause for her symptoms. That open question does not erase the reversal. It shows how hard brain and nerve medicine can be. It also raises a core safety rule: measure twice, cut once. When the stakes are lifelong drugs and life plans, the bar for certainty should be high.
The human and financial costs of a wrong label
The 2019 specialty-center study did more than count errors. It described harm that follows a wrong diagnosis: exposure to strong drugs with real side effects and a delay in the right care for the true illness. Disease-modifying treatments can help the right patient. They can also suppress immunity and strain budgets when directed at the wrong target. Families plan housing, work, and money around a diagnosis. A reversal resets all of it and shreds trust in the system.
A multiple sclerosis expert answers questions about MS misdiagnosis after Christina Applegate said she doesn't have the chronic condition after all. pic.twitter.com/Z1pYYB190z
— CBS Sacramento (@CBSSacramento) October 21, 2026
Patients deserve straight talk and second looks. A clear path helps: ask your doctor to link each symptom and scan to the exact rule it supports. Ask a neuroradiologist to re-read your MRI. Get a spinal tap only if the result will change the decision. Seek a second opinion from a dedicated multiple sclerosis center before starting long-term therapy. These steps are not distrust; they are due care when a label can shape decades.
How to square the 20%, 15%, and 10% figures
Each number answers a different question. The “nearly 20%” came from people referred to academic clinics because something did not add up. That group will always show a higher error share. The pooled 15% estimate combines mixed settings and study designs, which smooths peaks but still reflects selection effects. The 10% view from an experienced neurologist reflects caution about broad claims and the reality that everyday practice is not a specialty filter.
The takeaway for a conservative, common-sense lens is simple. Do not inflate a narrow statistic into a national crisis. Do not ignore a real problem because a celebrity said it out loud. Demand accuracy upfront, transparency in criteria, and accountability when the system gets it wrong. Precision protects patients and keeps scarce health dollars aimed where they do the most good.
What should change now
Health systems should require a checklist that ties each diagnosis to clear criteria before starting strong drugs. Payers should encourage second opinions for lifelong treatments. Academic centers should publish plain-language summaries of common look-alike conditions and red flags. Researchers should run prospective studies in community and academic clinics to measure true error rates. These moves are not flashy. They are the guardrails that keep families from swerving off the road.
Sources:
cbc.ca, cbsnews.com, psnet.ahrq.gov, people.com
