Christina Applegate Says Doctor Reversed Her MS Diagnosis

Actor Christina Applegate is reconsidering a major part of her medical history after her doctor told her she may have been misdiagnosed with multiple sclerosis (MS). The Emmy-winning actor disclosed the development Monday on her podcast, MeSsy, explaining that she continues to experience severe symptoms despite the revised assessment.

Applegate publicly announced her MS diagnosis in 2021. The neurological disorder occurs when the immune system attacks cells in the central nervous system, potentially affecting movement and other bodily functions.

During the latest episode of MeSsy, which she co-hosts with fellow actor Jamie-Lynn Sigler, Applegate described the uncertainty surrounding her condition.

"I'm back at square one where I don't know what's going on with me," Applegate said.

Although her doctor has reportedly questioned the original diagnosis, Applegate said her physical limitations remain substantial. She explained that she still needs mobility assistance when attending medical appointments.

"I still have every symptom of someone with MS. I still have to use wheelchairs when I go to the doctor's office. I can't walk from the car to the room," Applegate said.

Applegate also described feeling conflicted because she and Sigler have become prominent advocates for people living with MS. The uncertainty has affected how she views her role in that community.

"It's weird because I feel like I let everybody down," Applegate said.

She also described the emotional impact of learning that the diagnosis she had shared publicly might not be correct.

"It's very unnerving, and it's really confusing for me," Applegate said.

Multiple sclerosis can be difficult to diagnose because no single test definitively establishes the condition. Doctors typically assess symptoms, medical history, magnetic resonance imaging (MRI), spinal fluid findings and other tests to rule out disorders that can produce similar symptoms.

Benjamin Greenberg, a neurologist specializing in multiple sclerosis and autoimmune neurological disorders at UT Southwestern Medical Center in Dallas, said the most reputable studies estimate that 10% of MS diagnoses are incorrect.

Greenberg explained that diagnostic decisions depend on several forms of clinical evidence, and the process does not follow one universally standardized set of tests.

"We rely on the clinical symptoms, the history, the MRI, often spinal fluid, and then a series of tests to rule out potential mimics. And unfortunately, those tests are not universally codified," Greenberg said.

He said an initial diagnosis can influence subsequent medical assessments, potentially making clinicians less likely to consider alternative explanations. Such assumptions can affect how information is interpreted across the health care system.

"If I put 'multiple sclerosis' as a diagnosis on an MRI, a radiologist is far less likely to say, 'Well, this isn't multiple sclerosis. You really should consider something else.' It can permeate the system," Greenberg said.

Greenberg said Applegate's experience highlights the importance of reassessing diagnoses when the evidence does not fully support them. He also recommended that patients and families consider seeking another medical opinion when facing a serious or chronic condition.

"For patients and families, my general recommendation is whenever receiving a significant serious or chronic diagnosis, if feasible, there is never a harm in getting second opinions," Greenberg said.

Applegate has previously discussed the physical effects of her unexplained symptoms while promoting her memoir, You with the Sad Eyes. She has described needing diapers and moving down stairs on her buttocks as her condition has affected everyday activities.

In her memoir, Applegate wrote about the extent to which her life had narrowed because of her health difficulties, describing how her physical limitations had restricted her daily world.

"My life has in some ways shrunk to the size of my California king," Applegate wrote.

Medical experts note that autoimmune diseases often arise from a combination of genetic susceptibility and environmental factors rather than a single genetic defect. Potential triggers can include infections, smoking and exposure to pollutants, although the cause of an individual patient's symptoms requires separate medical evaluation.