Christina Applegate says she was misdiagnosed with MS

Actress Christina Applegate says she was misdiagnosed with multiple sclerosis (MS), a neurological and autoimmune disorder.

Applegate, 54, made the revelation Tuesday in a new episode of the MS-focused podcast, "MeSsY," which she co-hosts with actress Jamie Lynn Sigler, who has been public about her own battle with MS.

“This may come as great news, but to me, it comes as like, very like I'm back at square one," Applegate said. "But it's hard to say … [my doctor] came into my room and she said, 'Congratulations, you don't have MS. Congratulations.'"

Applegate first publicly announced in 2021 that she had been diagnosed with MS, a disorder which causes the immune system to attack the cells in the central nervous system, according to the National Institute of Neurological Disorders and Stroke.

She spoke as recently as March, in an interview with ABC News' Robin Roberts, about her struggles with the condition, saying she had not yet accepted her diagnosis and added, "This is a lifelong disease with no cure. Period."

On the podcast, Applegate revealed that she still has "every symptom of someone with MS" and said the shocking news of her misdiagnosis has left her with more questions than answers.

"If anything, I've gotten worse in some ways, and so I'm back at square one that I don't know what's going on with me," Applegate said. "And that's going to be an online investigation that, you know, my doctors are going to get into, and just to find out what has been happening since 2021. Why did this happen?"

She later added, "It's very unnerving and it's really confusing for me."

There is currently no single test used to diagnose MS. Instead, diagnosis requires a comprehensive evaluation that may include neurological exams, MRI scans and laboratory testing. MS symptoms can be unpredictable, varying in timing and frequency and ranging from fatigue and numbness or tingling to weakness, poor bladder control, dizziness and vertigo.

There is also currently no known cure for MS and typical treatment consists of medications to reduce flares and slow the progression of disability. 

Applegate said she took a hiatus from the "MeSsy" podcast to give herself time to "process" her misdiagnosis, which she said put her in a "great depression."

"I still have to use wheelchairs when I go to the doctor’s office. I can’t walk from the car to the room. I’m still in this," she said. "Nothing magical happened when [the doctor] said, ‘You don’t have MS.’ Nothing magical happened.”

Applegate -- whose last major acting role, Netflix's "Dead to Me," concluded in 2022 -- said she has also been left feeling without a community without her MS diagnosis.

“It’s weird because I feel like I let everybody down,” the actress said. “It’s this weird feeling because I became this — [Sigler] and I, the poster children for MS. And everything I was doing. I had a reason ... And now I don’t have a reason and it’s very unnerving and it’s very confusing for me.” 

In a follow-up episode, Applegate and Sigler spoke with Dr. Marwa Kaisey, an associate professor of neurology at Cedars-Sinai Medical Center in Los Angeles, who said that Applegate is not alone in being misdiagnosed with MS.

Kaisey said that in her research, she found nearly one in five people are misdiagnosed with MS. She attributed the rate of misdiagnoses to both the lack of a single test to diagnose MS and the fact that many MS symptoms are "very common in other things that are not MS."