Gavin Giovannoni, MBBCh, PhD, FCP, FRCP, FRCPath, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK, discusses the problem with classifying multiple sclerosis (MS) into four individual diseases. The origin of these categories stems from the first clinical trials of MS in their attempt to gain orphan drug status. Therefore, these categories are not based on the biology of the disease which leads to huge implications. For example, individual clinical trials for each category of patients are more expensive and the development to more progressive forms of MS can result in a roadblock in eligible treatments. Prof. Giovannoni concludes that treatment should be based on the biology of the disease and active inflammation, regardless of the subtype of MS. This interview took place during the Virtual World Congress on Controversies in Neurology (CONy) 2020.