Christina Applegate’s Story Shows Why MS Can Be Misdiagnosed

WHO:

PBS - Actor Christina Applegate said she had been told she did not have multiple sclerosis (MS) after previously receiving an MS diagnosis.

PBS - Applegate co-hosts the podcast “MeSsy” with actor Jamie-Lynn Sigler.

PBS - Dr. Michael Kornberg, an associate professor of neurology at Johns Hopkins University, discussed MS diagnosis and misdiagnosis with PBS correspondent William Brangham. Kornberg said he had not treated Applegate or reviewed her medical records.

The Washington Post - Applegate is an MS advocate and has described herself as the “poster child” for multiple sclerosis.

The Washington Post - Applegate and Sigler co-host “MeSsy.”

WHAT:

PBS - Applegate said her doctor told her, “Congratulations. You don’t have M.S. Congratulations.” Applegate said she was “not happy at all” because she remained unwell.

PBS - Applegate said she was “back at square one,” did not know what was happening to her, and had “every symptom of someone with M.S., every single one.”

The Washington Post - Applegate said new testing led a doctor to reconsider her MS diagnosis. She said her condition had “if anything … gotten worse, in some ways.”

PBS - Estimates of MS misdiagnosis vary from 5 percent to as high as 40 percent in one analysis. Kornberg said that in specialty clinics with experienced MS neurologists, an estimated 5 to 10 percent of people diagnosed with MS are later told the diagnosis was incorrect.

PBS - Kornberg said most MS diagnoses are clear, but a sizable minority are not; he cautioned that people with MS should not assume they were misdiagnosed.

WHERE:

PBS - Kornberg is affiliated with Johns Hopkins University; the interview discussed care in specialty clinics and diagnosis involving the brain and spinal cord.

WHY:

PBS - Kornberg said MS can be difficult to diagnose because the brain and spinal cord are not easily accessible for testing, there is no single definitive test, and other neurological conditions can cause symptoms or MRI abnormalities resembling MS.

PBS - Kornberg said a changed diagnosis can be distressing because symptoms remain, the cause is still unknown, and patients may lose the reassurance and identity associated with an MS diagnosis and community.

HOW:

PBS - MS diagnosis relies on typical neurological symptoms and typical brain and spinal-cord MRI findings, sometimes supplemented by other tests; Kornberg said there is no blood or spinal-fluid finding shared by everyone with MS and absent in everyone without it.

PBS - Kornberg advised people with concerns to seek a second opinion, consult a neurologist experienced in MS, and discuss unusual or atypical symptoms openly with their neurologist. He identified fatigue and pain as common MS symptoms that are also common in other conditions.

(UPDATED October 23, 2026 11:07 UTC)

Actor Christina Applegate says a doctor reconsidered her multiple sclerosis diagnosis after new testing, but she remains unwell and still does not know what is causing her symptoms. Applegate, who co-hosts the podcast “MeSsy” with fellow actor Jamie-Lynn Sigler and has spoken publicly about living with MS, said her doctor told her, “Congratulations. You don’t have M.S.” She said she was not happy, felt back at square one, and still had symptoms associated with the disease. Johns Hopkins neurologist Dr. Michael Kornberg says MS can be difficult to diagnose because there is no single definitive test, and other conditions can resemble it on scans or cause similar symptoms. He said most diagnoses are clear, but some are later overturned; estimates of misdiagnosis vary. Kornberg advises patients with concerns to seek a second opinion from a neurologist experienced in MS and discuss unusual symptoms openly.