There are almost as many different forms of Multiple Sclerosis as there are people with the disease. Each person with MS has a slightly different clinical (and symptom) profile; the precise course that any one person’s Multiple Sclerosis will take is not as predictable with the kind of detail that many people with the condition – as well as their doctors – may wish for. In this context, scientists and doctors are always trying to refine their classification of types of MS, as they get to know more and more about the condition and its symptoms. You may therefore come across several slightly different ways of describing types of MS.
There are several main types usually described:

• Relapsing-remitting Multiple Sclerosis. Many cases initially take the form of what is generally described as relapsing-remitting MS. especially in younger people. Symptoms worsen during an ‘attack’ or ‘relapse’ or ‘flare-up’, may be at their worst for several days or a little longer, and then gradually improve in the following weeks.
• Chronic progressive (or primary progressive) MS. This describes another pattern where symptoms gradually worsen after the first ‘episode’ or ‘attack’, with a continuing increase in disability; often this will involve deterioration in bodily movement (described as motor symptoms) of one kind or another, or sensory performance (especially eyesight).
• Benign Multiple Sclerosis. This is a term sometimes used to describe a course of MS in which symptoms are relatively minor, or progression is so slow that it is almost clinically imperceptible, or there are very few attacks or relapses over long periods of time – usually 15 years following diagnosis. There is growing evidence that the course of MS is likely to be initially more benign, almost irrespective of initial symptoms, for those people with fewer lesions (plaques) detectable in the CNS with a scan, compared to those who have a larger number. Unfortunately, the evidence from long-term research is that most benign ‘cases’ of MS do eventually result in significant symptoms and disability, even though this may not occur for 20 or 30 years after diagnosis.
• Secondary progressive Multiple Sclerosis. MS can also change its form so that, for example, relapsing-remitting MS may change into what is called secondary progressive MS – when a relatively steady decline begins to occur and remissions grow less frequent.

Finally, in case you hear this point from other sources (but don’t worry about it unduly), there is what some think to be a very, very rare variant of MS (others think it might be a separate disease), that can lead to death in a few months. This is sometimes, although completely misleadingly, described as malignant Multiple Sclerosis. There are also other rare types (for example, opticospinal MS).