Skip to main content
Multiple Sclerosis

What Is Clinically Isolated Syndrome? A Neurologist Explains

Lauren Smith, MAMandy Armitage, MD
Written by Lauren Smith, MA | Reviewed by Mandy Armitage, MD
Updated on April 7, 2025
Featuring Michelle Fabian, MDReviewed by Mandy Armitage, MD | April 7, 2025

You may know that multiple sclerosis (MS) involves repeated attacks on the central nervous system, causing episodes of neurologic symptoms. Clinically isolated syndrome (CIS) is when you experience a first episode, and it may or may not lead to the development of MS.

References

Miller, D. H., et al. (2012). Clinically isolated syndromes. Lancet Neurology.

National Multiple Sclerosis Society. (n.d.). Clinically isolated syndrome (CIS).

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

why trust our exports reliability shield

Why trust our experts?

Lauren Smith, MA
Written by:
Lauren Smith, MA
Lauren Smith, MA, has worked in health journalism since 2017. Before joining GoodRx, she was the senior health editor and writer for HealthiNation.
Mandy Armitage, MD
Reviewed by:
Mandy Armitage, MD
Mandy Armitage, MD, has combined clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

Was this page helpful?

Latest articles