Abstract
Multiple sclerosis (MS) refers to scattered areas of hardening found on sectioning central nervous system tissue of affected people, usually after many years of illness. It rarely causes early death but is the commonest cause of neurological disability among young people. Overall results from controlled trials over the past 50 years have been rather disappointing but the comparatively recent licensing of drugs such as interferon beta and glatiramer acetate has led to a reappraisal of many aspects of MS. There are now new diagnostic criteria, which encompass developments in magnetic resonance imaging. Older clinical methods of measuring disease impact are now being re-evaluated to facilitate clinical trials of the approximate 150 new products currently being developed as potential disease modifying agents. The success and failure of agents that should be effective on theoretical grounds, together with advances in neuropathology, have led to fundamental questions regarding our basic understanding of disease pathogenesis being re-addressed.