What Christina Applegate’s misdiagnosis reveals about MS

Christina Applegate at the 2023 Screen Actors Guild awards. | Valerie Macon/AFP via Getty Images Christina Applegate, the actor who has been one of the most visible faces of multiple sclerosis since her 2021 diagnosis, made a stunning revelation this week: She does not have MS after all.

And her doctors still don’t know what is causing her debilitating symptoms.

“I’m back at square one,” Applegate told fellow actor Jamie Lynn Sigler, who does have MS, on Sigler’s podcast MeSsy .

“I was not happy at all.

Everybody else was so happy.” It is a harrowing predicament for Applegate, and hopefully her medical team is able to get her the diagnosis and treatment she needs.

But the fact is, her experience is not unique.

Even as more and more Americans get diagnosed with multiple sclerosis, misdiagnosis remains all too common.

According to one meta-analysis, roughly 15 percent of MS diagnoses may actually be false positives .

How could such a common medical condition — roughly 1 million Americans are living with the disease, about one in every 350 people — remain such a mystery? After Applegate’s announcement, I called some leading experts on MS to ask why diagnosing the disease is such a challenge, and what they want people to know.

Here’s what I learned.

Why MS can be challenging to diagnose Multiple sclerosis is an autoimmune condition: The body mistakenly attacks cells meant to protect your brain and spinal cord, and the resulting damage interrupts nerve signals and causes the disease’s telltale symptoms of motor impairment, tingling sensations, and vision problems.

Some people experience a rollercoaster of relapses and remissions; others see the disease steadily progress, eventually leading to serious disability.

The reality is, scientists still don’t really know what causes MS to develop, said Dr.

Andrew Solomon , a neurologist at the University of Vermont who specializes in MS.