Christina Applegate, the actress who has openly discussed her experience with multiple sclerosis (MS) for several years, disclosed on Monday that her diagnosis was incorrect. During an episode of “MeSsy,” the podcast she cohosts with Jamie-Lynn Sigler—who also has MS—Applegate revealed that her doctor informed her she does not have the autoimmune disease.

Applegate, who announced her MS diagnosis publicly in 2021, described the news as both confusing and unsettling. “I’m back at square one where I don’t know what’s going on with me,” she said on the podcast. Despite the absence of a formal MS diagnosis, she continues to experience symptoms consistent with the disease. She noted ongoing mobility issues, including the need to use a wheelchair at medical appointments and difficulty walking short distances.

Multiple sclerosis is a complex condition that lacks a definitive test, often requiring extensive evaluation and the exclusion of other potential causes before confirmation. This process can take several years, with patients seeing multiple specialists to arrive at an accurate diagnosis.

Applegate expressed feelings of disappointment and concern about how her revelation might affect those who have supported her and her advocacy efforts for MS awareness. “It’s weird because I feel like I let everybody down,” she said, acknowledging the emotional toll of the situation.

The causes of autoimmune diseases like MS are not linked to a single genetic defect but rather to a combination of genetic susceptibility and environmental factors such as infections, smoking, or exposure to pollutants. These elements can trigger the immune system to attack the central nervous system, leading to the diverse and often unpredictable symptoms associated with MS.

Throughout her public discussions and in her memoir, “You with the Sad Eyes,” Applegate has been candid about the challenges she faces. She has described symptoms severe enough to require the use of diapers and has shared instances of navigating daily life with significant physical limitations. In her memoir, she reflects on how her world has contracted due to her health struggles, asserting that her life has, in some ways, “shrunk to the size of my California king.”

Despite the misdiagnosis, Applegate’s openness has contributed to broader awareness about the complexities of MS and the need for continued research and understanding of autoimmune diseases.