Actor Christina Applegate said this week that her doctor told her the multiple sclerosis diagnosis she announced in 2021 was incorrect. On her podcast "MeSsy," she said she still experiences every symptom of MS and relies on a wheelchair for long distances, but she is now "back at square one" not knowing what is wrong. Applegate, who co-hosts the show with fellow MS advocate Jamie-Lynn Sigler, said the reversal feels strange and that she worries she has let people down.
MS misdiagnosis is a known problem, though its frequency is debated, said experts quoted by MedPage Today. Marisa McGinley, a neurologist at the Cleveland Clinic, noted that studies report rates from under 10% to nearly 20%. Bruce Bebo of the National Multiple Sclerosis Society cautioned that figures often come from specialty referral centers, which tend to see the hardest cases.
There is no single diagnostic test for MS. Instead, doctors rely on the McDonald criteria, last updated in 2024, which typically require characteristic MRI lesions and a careful exclusion of other conditions. As Bebo put it, diagnosis is "like putting a puzzle together." The case highlights the ongoing tension between diagnosing MS early and avoiding errors. "We can't sacrifice speed for accuracy," he said.